I Have Had These Marks Come Our On My Skin

I have had these marks come our on my skin since I was a teenager, I'm now 23. They look like raw burn marks but it's like my skin dissolves itself. It doesn't happen all the time but when it does I feel really run down and rubbish. When I was younger my doctors said I was doing it to myself which has put me off getting it checkEd out but I'm really fed up now. Please help