By Daniel Chavkin The head coach was dealing with an ever more formidable opponent than Michigan. Sonny Dykes is about to coach the biggest game of his career, but the TCU head coach has been dealing with a different kind of battle at home. While appearing on College Gameday Saturday morning, Dykes revealed he has a cut on his head. Pat McAfee thought the head coach was going extra hard in practice, but it turns out football has nothing to do with it. “I’ve got a six-year-old son, man. I mean, I’ve got a different injury everyday,” Dykes said. “I had a swollen eye earlier in the week, so I loo…