This needs to be biopsied again, perhaps they did not go deep enough. I know this is possible as it happened to me. I had a tumor under the surface that an initial biopsy did not catch! ;( I don't want to scare you - But I would rather have you go back and get it checked than discover a tumor when it is more advanced. Better safe that sorry. Plus sitting there concerned is no way to live - it takes its toll mentally.
It could very well simply be swollen because of the biopsy - or even infected, but have it checked regardless.
hugs