How to get rid of stretch marks and discoloration on buttocks?

I never had kids or gained a lot of weight I'm quite slim. I have had these for about 4 to 5 years with no reasoning. My mom or dad never had this problem. I'm only 100ibs 5'7. Also the discoloration is killing me it kinda like like different color patches. How do I get rid of this?

No doctor answers yet