Hopefully not, maybe they just needed more room, they don't do well when in close quaters. you may try putting some triple antibiotic ointment on it. Let us know how they are in a few days. But don't get scared an run out for antibiotics not a good thing to treat with unless you know what your treating. pics of injuries would be good too. Lots of very helpful folks here.
I put some of that Blu-Kote on it using my finger to dab it on. They look less swollen today and actually looks like the blisters have dried up. I really think that one chick pinched the others.