Water filled blister in soft palate.

In the month of April I was diagnosed with strep throat...I was advised antibiotics and I did daily salt water gargle...From the month of May I am feeling discomfort in my soft palate (palatoglossal area)...Every time I eat a small water filled blister arouse which subside slowly..but not fully... The picture which I have attached is two months old.this blister occurred after eating dinner but subside after rising mouth by warm salt water... I took becosule for one month... Now taking polybion syrup and evion 400... But still not got rid of it. Always it appears after eating...and stays all day long and subside in the morning little bit.. I don have pain in that area.. I am scared...please advice me what to do.. In between I have consulted a dentist...he told nothing to concern..it's seems like simplex herpes and advised me to take fresh vegetables,fruits and protein.. Plz guide me..I am very much scared...