You can surely have these vit b12 c and folic acid tablets. But it is still advisable that you consult a dentist
to get clinical evaluation done and the proper history of your complaint is established which will help in determining the cause and removal of the ulcer
. After evaluation of the lesion extent and the severaity treatment will be given accordingly.
Till then you can apply mucopain gel on the affected area as in when needed.
Kindly follow the advice and put an end to your sufferings:)