Jhonny Lion,
I'm sorry for your level of worry but I have to ask you if you've been to the doctor with these concerns. Before you worry about how bad treatment can be, you need to confirm it's even relevant. Does this make sense?
I'm not sure who prescribed the antidepressants but please consider speaking to them as well. If your anxiety level is high, maybe your medication needs to be addressed. I, personally, don't think at your age you should let things go from a sore to fear of a disfiguring surgery. There are many steps between the two and you need to pursue these sores with medical professionals as soon as you can.
I don't think it is cancer but I'm not a medical doctor. If it is, just another reason to get to a doctor soon.
Hang in there, young man. I'm certainly hoping it's nothing. Please let us know what your doctor says.