Okay, I can't remember much, but I know it was very well written and a great read.
Xander runs across a group of guys beating on someone and he runs over to help the person out. I think he kills one of the guys...He finds out it's Spike that was beaten and takes care of him. It a wonderful H/C and Xander is so loving and protective in it.
ETA: The first one is Healing by jameschick
The other one is a genderbender. Spike turns into a girl and Xander takes care of him. Spike has his chip, and Xander acts almost like a bodyguard around female!Spike. Another H/C and another great read.
ETA2: The Second one is The Girl Series by Pet!