Tonight at 7:20 ish Carbon started acting very weird. She was zipping around the cage like crazy, running laps and jumping on pigloo and over her piggie sisters. After about five minutes I got in and had a good look at her and there was a milky substance matting her hair down and apart on her back. Once I got a flashlight and really looked it looks as if she bit herself so much that she cause a cut. Up until now she's been perfectly fine (I do remember an odd scab/bump in that location on her back months ago but it disappeared after a week - I believe she was scratched by a new piggie I introduced then separateld from her) the past few days she's been just like she normally has been. She's ate her veggies, her hay, and her pellets. She's been drinking water and playing with the other girls. Ten to fifteen minutes ago is when this all started and I don't know what to do. I've cleaned her up the best I could without hurting her anymore than she seems to be. She's now just laying in my lap, still very alert and moving. I plan on calling my vet tomorrow morning when they open at 8 and trying to get her in as soon as possible. Any help or advice or even just to help me know what's happening would be greatly appreciated. I added photos of the wound, they're not too great but I tried. The last is after I cleaned her.