Can I Take Phentermine After my Tummy Tuck?

I had a circumferential Tummy Tuck 4 weeks ago. Prior to surgery I was told to stop taking my phentermine 2 weeks prior to surgery which I did. I am now 4 weeks post op and recovering but have gained 4 lbs. being stuck in the house not moving much does not help. My surgeon told me while he isnt telling me to take phentermine that if I wanted to that it was safe as you can go back to it as of 3 weeks post op. I wanted to get other doctor's opinions on this. As he wants the weight back off.