I noticed it about a week ago. It doesn't hurt unless I really squeeze it. I'm slightly worried it could be a tumor or skin cancer, but a tumor is more likely, I read the skin cancer usually only occurs on the main parts of skin. Is it likely it could be one of these? I'm 16 if this helps. Please Help!

The first thing is to ask your doctor.

Also, just so you know, it could be an allergy to an earring you are wearing. Do you wear earrings? If I wear anything but 14K gold or up, or sterling silver, I get a lump as an allergic reaction. It goes away w/in a few days of not wearing that earring anymore.

No, I don't wear earrings.