Chill guys, I think he blushed because its unexpected that she touched his cheeks. If you think about it, his past is pretty shitty (so social and physical contact besides getting beaten is not normal for him)
I understand why she doesn't see him as a love interest. After all, he's younger than her and at an age of discovering (even tho not by a lot, but still), if it was an older guy and she's being oblivious then it would be quite annoying.