My youngest guinea pig seemed to have hurt his front leg. I tried looking at it and it doesn't look swollen or have any scratches, but he keeps holding it when he walks. I'm pretty sure my oldest guinea pig did it to him (they are only a month apart but my youngest is the runt of the group). He is still eating fine, but I'm concerned still. Is there anything I could do to help him? (Also my eldest guinea pig hasn't hurt anyone else and doesn't seem aggressive so it may not have been him.)