My dad has bed sore on his foot somewhere between stage 1 and 2. It hasn't broken open yet, but it is definitely poking out and there's a tiny line, sort of like a paper cut. It's yellowish in color. I can tell it's about to go into stage 2 soon. He received antibiotics and pain pills this morning, but he forgot to ask this: what should he use as a barrier between his foot and sock/shoe while being barefoot is not an option?