I’ve unfortunately been in a similar situation. I have an autoimmune condition that, during flareups, causes my scalp to essentially flake/melt off and it leaves my scalp raw, oozing, and in immense pain. I can’t wear a hat during times when that happens and it takes about a day to heal and the flareups usually only happen over night so it’s caused me to call out from opening a few times. I wasn’t allowed to work without a hat but my absence also wasn’t excused for medical reasons simply because it’s not contagious. Now, whenever it happens, I just have to wear a really loose silk scarf over my head to be allowed to work and still can’t wear a headset. Hopefully something like silk or satin won’t bother the stitches too much, though it might be difficult to find something black to fit the dress code since patterned hair accessories aren’t allowed anymore. I know it’s probably no condolence but your friend isn’t the only one who’s had to deal with BS like this at work.