Guys, it's light reflecting on the plain black shirt, you can see pics of him in the same scene in other shots, no skull. I really hope I am wrong, but I wasn't about other Marvel tv adoptions screwing up the characters looks. Hell, we didn't even see Matt actually wearing a real costume till the last quarter of the final episode of the first season.
I don't get with Disney owning them, why budgets are this much of an issue. If you can't properly dress your characters, it's time to ask the bankrollers for more money to do it right. Otherwise, you get a Fantastic Four instead of a Deadpool.