hello and welcome to HCM forum,
first of all i would like to inform you that it is lichenoid reaction if i am taking you right, this is an
allergic response which occurs due to a number of factors, some of them include;
oral medication or
drug interaction, dental fillings(amalgam), alcohol intake,etc.
therefore, do not worry these symptoms subside gradually once the irritating agent is removed and as you mentioned your
dentist has already checked and prescribed you a topical gel. this will definitely resolve the symptoms, you just have to make sure to maintain your
oral hygiene by using antibacterial mouth rinse.
also visit your dentist at regular intervals, to make sure that this reaction has subsided .
just be calm and keep applying the gel,
i wish you good health,
take care.