Same thing happened to us - about 3 wks ago and we KNOW it was the rooster. The gaping hole was sooo big you could fit an egg in there. We used bag balm (only thing we could find) and wrapped her up. She removed the wrapping and wimpered in her lonely little cage. We fell for it, and returned her to the flock. 10 days later, we find a new matching hole on the other side!!!! Rooster lost his spurs that day. We bought a baby bib at the $ store and put it on her backwards. She HATES it!!! She's removed it once and moves it outta position, but we continue to restore it to the proper position. It goes under her wings and covers her back and wounds. We've used blue kote and it seems to be helping. She was picking at her wounds keeping them from healing.
Knowing the rooster would be sore after spur removal (not trimmed , completely removed the outter shell) we kept him from the hens. In less than 10 minutes he found a way in and was mounting hens. Kept him away from the wounded one, but the other night it was cold and we put them all in together - yep - he mounted her bib (aka chicken saddle) and all!