Welcome to HCM.
The chances of getting HIV through kissing is negligible. Installation of crown for tooth also carries no risk for HIV.
So nothing to worry.
Sores of mouth is a very common for anybody and not necessarily due to HIV.
As you had been disturbed mentally, I suggest you to go for HIV test
to see a negative result. Only after seeing your negative result you can relax. As it is already more than 7 weeks over after the incident , you can have the test after another 3-5 weeks time.
Good day to you.