Could it be skin cancer?

I noticed one day this past summer, there was a sting on my back. It felt like a bee sting. So, I went inside and had my husband spray some benadryl on it. He told me he couldn't really see anything, but sprayed it for me anyway. It went away the next day. A few weeks later, it came back, and went away again. There is a tiny, flesh-colored bump there now, but it sparatically hurts really bad. I have an appointment at my dermatologist's office at the end of next month (about a month away). Until then, I'm going crazy worrying. My grandparents have both had several melanoma removed. So, I have always been VERY careful as far as always wearing sunscreen. I'm wondering if this could be something serious? Do the symptoms sound familiar?