Sherry was shot at in the last episode by male members of Anti-Skill and almost had a hand grenade tossed at her so..
Spoiler for ep.23:
A punch to the face is pretty minor in the scale of things here.
If anything, it's "Go Sherry". She took a punch to the face that sent her flying and was still able to make that rune for her escape. Then was able enough to attempt to attack Index who we finally saw a little bit of what she's capable of.
So I also say "Go Index!". Take that detractors who said she was useless. She did more damage to that thing than Touma did.