superficial numbness in left calf?

I had some problems with my left knee/calf that I saw a physiotherapist for a little while ago. We treated the problem for about a month, thought it was fixed, and that was that. I am not having any of the pain that I was having before, but now I am experiencing numbness around that entire area down to my ankle and across to my shin. I haven't seen the physio in a few weeks now.

Time to go back to the physiotherapist or should I bring this to my GP? Or is this something else that will just pass in time?