Hi. My name is Deb.I had brain surgery last August (9 months ago) and was prescribed Dilantin for about three weeks. My gums built up and pulled away from my teeth, leaving large gaps around two of them which remain to this day. I also have a lump in my neck that has persisted for about 3 months now. Could these be side effects of a med I took for such a short time? By the way, my dentist referred me to my family doc, who referred me to an ENT specialist. I am due for an MRI in a week to hunt for residual brain tumor (one of the tumors had to be left in my head); my family doc amended the order for an MRI of the neck. I m just hoping this is benign and not malignant. I do have a history of melanoma, but it was on the arm, nowhere near the neck. I also have a nevus (so far, fingers crossed!) on my retina, same side as the lump on my neck, nestled under the mandible. The lump is big enough that I can t feel the top of it under my jaw. Probably have to wait for results of a core biopsy to find out what this thing is. Ya think?