I have 2 unrelated issues I'd like to get feedback on (for 2 different people actually...)

First, my mom has been having issues with her fingernails for months. It was as if the nail bed, underneath her nail, was getting smaller as the nail bed separated from the nail. It made them very hard to clean and maintain and seemed to be getting worse. Her derm thought it was from trauma and prescribed biotin. It helped for awhile, but then other nails began deteriorating as well. When she went back she diagnosed her with psoriasis of the nails. Has anyone encountered this before? She's frustrated because there doesn't seem to be anything she can do about it and the huge gaps under her nails are potentially problematic. I don't think she's happy with the cosmetic issues either, but mostly the idea of having these gaps under her nails is frustrating. Please let me know if you have any experience with this diagnosis or can point me in the right direction to learn more.

Second, my friend is planning on getting a tattoo over some of her stretch marks on her inner arm. They are old, white/silvery, and not that wide, but still clearly there. My research has led me to believe that the older, smaller, and lighter the stretch marks are, the better they will do under a tattoo. Also for whatever reason black does better than color pigment. Other than these general guidelines I haven't found much else. I also read there is also potentially more pain involved, but she has lots of tattoos so I'm not too worried. The main issue is if the tattoo will work in the first place, bleed over time, cause her skin to blow out etc. Does anyone have experience with tattooing over stretch marks, new or old? I'd love to hear about positive or negative experiences just to give her some feedback.

Thanks everyone! I can't believe it's been so long since I've been on here, I miss it

-Bellerina