70mg isnt that much, depending on your weight. Im on a second course of 60mg, but have heard people on upto 120mg. 40-80 seems the "normal" range, but every derm is different.
My skin is dry, but I dont bother with sunscreen, and still drink while im on it. Not too much, I dont binge drink anyway, but it doesnt stop me having a couple down the pub on an evening. I put a bit of moisturiser on and some stuff for my lips. It might be because my dose has been all over the place this time (for 20-60mg/day) depending on what im doing and if I remember, but the results havent been fantastic. Derm was pleased when I went to see her, but I couldnt help think that I knew my own skin and it hadnt improved. Anyway, at least by under-doseing so much I'll have a lot of space tablets so its not going to be a 4 month course!