Reopening scab/burn , what can I do to stop it from reopening?

3 days ago I wasn't wearing knee pads and got like a rug rash type of thing on both of my knees wen playing volleyball. they are both the size of a half dollar but the right leg is much worse since the right knee is the one I normally fall on. the day after it happened I had v-ball again and it started bleeding in my knee pads. I had v-ball everyday for the rest of this week and next week, and everyday the scab keeps being reopened and keeps bleeding. I try hard to avoid falling on them but sometimes I can't, and I have practice all day ( 7 - 4) for the rest of this week and next week. I've already tried wrapping them under my knee pads but then they just start bleeding under the bandage. what can I do to stop it for reopening so it can finally heal? not to mention it hurts like u know what everytime I fall on it.