My 6yrs old boy fell down and there is a swelling below the knee. Two boils came after swelling. It got broke and pus came. Daily we are cleaning the wound and applying ointment. While standing up, he is having severe pain for a shorter time. After walking pain goes away. What could be reason. Any other home remedy. Please see the attached photo. Swelling looks small in the pic but it's a bit larger than that.