How do I increase the blood cerculation on my foot after having a knee surgery? Because it's been a month and I feel like there's pins when I walk

Healing nerves. When you have undergone a surgical procedure, it can take time for things to heal. The skin incision may be closed, but all the deep structures, such as nerves are still healing. In all likelihood, the circulation is ok. The "pins" definitely tell me nerves. It can take some time for this to subside. Swelling of the extremity could also cause these symptoms.
Is not circulation. You must tell your surgeon. The symptom is not the result of a circulation problem, especially in a 17yo!