Had PRP for hair loss and nurse told me to take ibuprofen. Now I know this can negate the effects of the PRP. What should I do?

Aspirin, ibuprofen, and naproxen are in a drug class called NSAIDS (non-steroidal anti-inflammatory drugs). They reduce pain, reduce fever, and in higher does, have anti-inflammatory effects. They also have anti-clotting actions, meaning that minor bleeding may occur at the PRP injection sites. The effect of this minor bleeding may result in  pain in the injected areas. While the pain may be bothersome, unless the bleeding were considerable, I am not aware of  any evidence that it would have an adverse impact on the treatment itself. 

Your use of ibuprofen after PRP is not likely to have an adverse effect on your results. I wouldn't be concerned.