Sorry to hear about your problem, but the only thing that you can do right now is to go to your dentist and have your teeth looked at. It is absolutely impossible to give you any critical information without a proper physical examination and looking at x-rays.

Many times, small areas of decay behind veneers or fillings can be fixed with another small filling. However, if the decay is extensive, you might have to have the tooth root canalled, have a post/core fabricated and a crown, or worse yet, the tooth might be non-restorable and will have to be extracted and replaced with an implant.

In any case, all this information cannot possibly be ascertained over this very limited forum.

Please go to see your dentist.