Hmmmmm...that's a good question. I'm the same way. My foster mom checked me every week or so for fresh marks on my skin...something I found that helped was lip balm or chap stick. Im not sure how it works in the healing process but for me it tones my cuts down and makes them less noticable. Remember if the cut get infected or something goes wrong you need to tell your parents about it. I suggest you tell your parents even if it's not tho. I self harm but I'm not proud of it and it is a bad coping habit that doesn't easily go away. I hope this helped.
and please stay safe