Semi-hard lump on upper back

Hi, I've got a pinkish-red lump on my upper right back and it's about 2-3 centimetres, growing bigger as my skin stretches. I've been to the doctors, but they aren't clear on what it is, but at the moment I'm getting injections on the lump which supposedly makes it softer and smaller slowly. I've had the lump for over two years (i think), and it supposedly started out as a mossie bite [not sure]. The doctors say it probably doesn't have to do with cancer, but it may be more dangerous when removed, as it might still spread and cause more lumps.

I have been told that I'm rather tend to be prone to scars (just maybe).

x