i have three guinea pigs, two of which were just introduced about a week ago. they are getting alone fine and playing well but one morning i noticed a cut on one's face. it almost looks white powdery around it and is scabbing a lot. i've been gently cleaning it and it doesn't seem to be bothering him, but i don't want to risk it getting worse. i attached a picture but obviously he didn't want to stay still so it's a bit difficult to see. any advice would be much much appreciated.