Try making some bone broth and having some every day. It made such a huge difference in my hair, skin and nails. I find coconut oil makes a big difference too - not necessarily applying it, but cooking with it. If you're using any seed oils, switch them out for CO and OO.
Almond oil is gentle to the skin, and good old lanolin is great but a bit sticky. I'd advise more fats and oil in the diet too, and at least 2 litres water daily.
I had dry skin issues before i went primal. upper arms, scalp, sides of nose, and a few random spots here and there. Nothing serious, but enough to be annoying when I'd get out of the shower and everything was flaking.
I've stopped using soap/shampoo and that has definitely helped a lot. Any time I try using either, I step out of the shower flaking as before.
Luke-warm rather than hot showers only helped a tiny bit. Coconut / olive oil are definitely useful topical applications, but they for sure are not solutions to the problem. I've tried tea tree/jojoba oil mixes for my scalp but that didn't seem to help any. I cut out nightshades for a few weeks but that didn't help any. I seem to notice more issues in the days after eating non-primal, so i try to focus on eating clean and that keeps everything in check for the most part
The biggest thing that improved my skin was installing a whole house water filtering system. Also eating more saturated fat has helped my ashy epidermis, mainly lard, butter and fatty meats.