Hi! I skateboard and weeks back, while going downhill, I sped up a little too much and so I fell on the road. I had normal skateboard injuries, nothing that I had not seen before and now it is all fine. However, after University today, I felt that my knee was hurting a lot even when only the cloth would touch it. I undressed to check it out and thought that it was because of the pimple. I burst it but the swelling and the redness didn't go away. It hurts more and more when I walk and it looks quite red when I walk around. What is the matter and is it serious?

This could be a subcutaneous infection. You should get it looked at by a doctor.