I've had this on ocassion before, too - I don't think it's something you should worry too much about. It's likely just dry skin
in need of moisturizing. The condom and friction from sex could have aggravated it. I've also developed this condition sometimes when masturbating freequently. Anyway - a good approach is to use a simple moisturizer on the affected area a couple of times a day. Also, try to give it a rest for a few days so that it can get back to its own tough self. When the flaky skin and/or red tender area(s) are gone, he should be back ready for action - good luck!