Not a pregnancy question

So I don’t know but for the couple of weeks I take a shower and get out I notice like dirt like on my legs/thighs and on my arms. I take water and use body wash but for some reason it doesn’t get off for some reason. The only way it gets off is by me rubbing it it off. My legs and arms are making me super insecure. I don’t know why my arms and legs are like this. When I take a shower and use a loofah it makes my arms completely red. I don’t know what it is.. I know I’m not dirty but it’s annoying. 😩 anyone have advice?