My male cat got a little mole like bump on his side near his ribs 3 or 4 years ago, then it grew gradually. About 6 months ago it grew suddenly until it was about the size of a quarter and it was about a quarter inch high. Then, a couple of months ago, it burst and we were relieved because we thought it would finally dry up and go away. Since then, our cat has licked the wound and about the time it scabs up pretty good, he bites it and opens it up again causing that spot to bleed. Is it a tumor of some sort? Will it eventually heal on its own? He is an older cat, and will be 16 years old this coming April. Also, since he got this bump, he has been especially susceptible to fleas and I have a hard time keeping his weight up to par, but he still eats well, and drinks plenty of water.