The shots are usually the worst part for me! And I too have had canker sores after. Not sure why.
I have had bad dental stories. As a kid, we went to a bad dentist. We did not realize how bad he was until later. After he quit, because he had so many lawsuits against him. Once he put 8 fillings in my mouth at once. My mom just dropped me off that day. I can't remember why.
Before he began the work, he said that some dental students would be watching. I didn't like that! But I was also a kid so was afraid to say anything.
Fast forward to maybe age 12. Bit into a candy cane on Christmas Eve. Extreme pain and had to suffer until the dentist's office was open again. This dentist was a friend of the family. He discovered that my tooth had broken off under the filling. Why? The filling put in by the bad dentist had been done wrong and her left air space under the filling. It was also discovered that I had no cavities where those 8 fillings had been put. This dentist surmised if anything the other dentist might have put them in due to defects in my teeth, but he wasn't sure. Some of my back chewing teeth had natural pits in them. But... He also noticed that my parents and brother also had dental work put in by this guy that he thought we didn't need. And for some reason this guy was into gold fillings.
Some years later, as an adult, I went in and needed to get a crown because the large filling on my back tooth had broken down. No pain before I went in. MAJOR pain after! Something went wrong and I needed a root canal. But this dentist did not do them on back teeth. Sent me to a specialist and I had to wait something like 6 weeks to get the work done. And in those day a root canal was a major thing. Took something like 5-6 hours to do. I could smell stuff burning. And I was not given a bite block like they have these days. My jaw was sore and bruised for weeks!
Then I needed another crown on that candy cane damaged tooth. Two of the dentist's daughters were working there at the time and they got into a fight over who was going to seat the crown. Ended up that the glue or whatever they use had set up and they were still fighting. Dentist came in. Broke up the fight and told the older one to seat it. But... She got sloppy with the glue. So when the numbness wore off, immediate pain. I had to go back in. Turns out that somehow the glue had slipped down under my gums. To get it all out, they had to cut open my gums and scrape it off. That left the tooth and gums in that area super sensitive. For years I had to treat the tooth at home with yucky tasting fluoride and I couldn't chew on that side.
Then I got braces as an adult. The only really bad teeth were the top two in the front. I'd had a gap there when younger but now they were overlapping slightly and once in a while, the tooth behind would get hung up on my lower teeth. And that hurt! Would appear mostly cosmetic and had it not been for that other problem, I would have left it. So I really only had braces on the 6 top front teeth but the wire extended to the back. These were the old fashioned, clunky sharp braces. Suddenly canker sores were the story of my life. And each time I needed an adjustment, I was in screaming pain for weeks! I had no idea how painful braces can be as an adult. I've been told that children's and even teen's teeth will move more easily so braces for them are usually less painful.
So... A dentist in the city where my dentist lived, died. He left his office to my dentist. So my dentist was trying to see that guy's patients as well as his own. He really only kept that office open for long enough for all of those patients to find another dentist. But in the meantime, he was seeing patients there as well. He saw me there one day. Can't remember now what he was doing but he had his hands in front of my face and his arms out but around my head. Was trying to remove something from a piece of equipment but it wasn't working because he was not familiar with this equipment. In the process of this, his hand flew into my nose, smacking it hard enough to give me a severe nose bleed! It would have been funny had it not been so messy and caused so much pain!
Then I got married and moved. While in CA, daughter broke my two front teeth. She was a toddler and sitting in my lap. Kept whacking her head back into me as toddlers do. Asked her to stop doing that. Then took a drink of my lime flavored water in a glass bottle. And *wham*! She backed her head into me again, making contact with the bottle. She screamed because the glass bottle hurt her head. I screamed, scaring her badly because not only did the bottle get shoved hard down my throat but my top two teeth got broken! Thankfully the dentist I was seeing at the time was able to see me the following day and do a repair. You can't tell that they were broken and they don't hurt now.
Then when we lived in NY, I was in our storage unit. An empty computer box fell and hit me on the side of my face. Immediate tooth pain! But I was going to the dentist the next day. So I told her about it. She said there was no problem! I insisted that there was! I wanted her to take an X Ray but she refused. I was no happy. And I didn't think she was a good dentist. I left there still in pain and tried to learn to live with it.
We moved back here to WA. I found a Dr. here. Complained of the pain. Although he couldn't really tell, he surmised that it was maybe a sinus or ear infection. Put me on antibiotic. Pain went away. Med ran out. Pain came back. I was sick of the pain! Hooked up with a dentist here before it was time for my next checkup. He did an X Ray and discovered that the roots of the tooth were dying. There was my pain right there! Had to do another root canal and crown. I was terrified but this root canal only took maybe 2 hours. They used a bite block and although my jaw was sore for maybe 2-3 days after, the pain was gone after that.
Have had one more root canal, several crowns and a few fillings since. Some fillings because the old ones were wearing out.
My only complaint at my current place is that one dentist kept insisting that I needed crowns due to cracks in my teeth. I think he just wanted the money from the crowns. The other two dentists are not crown happy.
I guess one thing that helps me is that my grandpa was a dentist. He died when my dad was 8 so I never met him. But my dad was expected to follow in his footsteps. He tried to be a hygienist while in the Air Force but it was not for him. However he told me horror stories about how dentistry used to be. Such as getting the patient to drink so whiskey prior to help with the pain. And I have seen the tools that they used to use. So whenever I think I am going through a bad dental time, I just think about that stuff and am glad that I didn't have to go through that!