I have a red scabby mark in between my shoulder blades on my back - is it just a normal scab or a sign of skin cancer? (photos)

A few days ago I was scratching my back and I scratched over a bump, and it was pretty painful for a few seconds. I kept feeling around to check if it was bleeding but I didn't have blood on my hands, but when I lifted my shirt this scab was there. I'm not sure if the bump was ever there before because I don't really take notice of my back. I also have a bit of back acne, but it's near the top of my back and rarely in the middle. I'm worried sick over this, could it be cancer? I'm 23 years old.