How do you stop pins and needles when you have drop foot?

Many ways. If the cause of foot drop can be treated then abnormal sensations can be controlled. Various drugs like neuron tin, cymbalta, (duloxetine) tegretol, etc can help. Also do not forget physical therapy.
Find problem first. The first thing to do is find out why you have drop foot; a neurologist can help, with a combination of history, exam findings, electrodiagnostic testing, and imaging. Once you know the underlying issue is addressed, possible symptomatic treatments include physical therapy, medications for neuropathic pain (e.g. Amitriptyline or gabapentin) and nerve blocks, depending on where the problem is.