What food are you feeding him? I responded on another post this morning that my Stig's wrinkles used to be like that, he lost hair in his 'tear-stain' wrinkles and caused it to look raw. Actually, one time they got so bad that a customer at Petsmart came up to me asking if his wrinkles were bleeding. After a month of switching food, he stopped losing hair in that area.
I use a 'flush' that I got from my vet to clean his wrinkles. This flush was recommended to clean his hives he used to get before we got a control of his diet, in case that some get infected. It's $20 a bottle which is a little expensive, but I wanted to continue using it for his wrinkles because of the potential of it getting 'raw-looking' again. Another benefit is that you can really notice a difference after a few consecutive days of cleaning.
So imo it's most likely the food.