small fluid filled vesicles in mouth

[N2017]

Hello,
I'm 23 years old, i don't smoke ,i don't drink alcohol, in a good health , 8 months ago i bited my buccal mucosa when i was eating it was very deep injury , then immediately afterwards many painful ulcers appeared also in other places  and i was diagnosed with aphthous somatitis , but then the problem changed that i started to get painless small vesicles inside my mouth,filled with clear fluid that appear in minutes  and disappear after few hours leaving red spots that disappear latter ,and by my tongue i can feel them and feel their remains, they appear on my buccae mostly ,sometimes on the soft or hard palatine ,and also
i noticed that they appear more after food , in the beginning i used to get many everyday and by time and ignoring them  they got less by number and smaller by size but i still have them everyday now i get 3 - 4 everyday,
and i am very worried of what i have ,so please did you have any such case ? and what is the solution ? and what is the cause ?
thank you

[Caryopteris]

Try switching to a toothpaste with fewer irritating ingredients.  Whitening toothpastes can cause problems, for instance.  Try Jason's all natural toothpaste.  

[N2017]

i would like to add that the vesicles in my mouth are maximum like 3 -4 mm in diameter or even less .... i get  very small ones...