About a month ago I noticed a dirt spot on my skin. I didn't think anything of it and washed it away. Well a month later it continues to return and now seems to be getting bigger. It washes away with water and I can scrape it away with my finger nail. But it keeps returning in the same exact place except now it is getting bigger. It seems to get worse if I am outside all day. I keep think it will go away but it doesn't. I have tried to search for information online but have got nothing. It doesn't itch, hurt, burn, or anything. It just consitantly returns almost everyday. Any ideas?