I did PRP for hair loss yesterday and mistakenly took 2 pills of ibuprofen and 2 pills again today. Will it still be effective?

It's best to hold off on them and choose extra strength tylenol instead.  I wouldn't worry this time but reconsider with your next treatment.The medications that can contribute to bleeding may interfere with your treatment by promoting some bleeding in the area.  Since the platelets are purposely separated from your blood and concentrated to be maximally purposeful, the addition of whole blood to the treated area my interfere.In good health,Ellen Mahony, MD

It doesn't mean that you won't have results, but keep in mind, it can take up to six months for results with prp. In our office, we combine prp with progesterone to improve outcomes. 

In my opinion, ibuprofen or any other nonsteroidal may possibly interfere with the effectiveness of PRP. The total number of platelets and growth factors   will not change, however the addition of red blood cells fro increased bleeding  may lead to a inflammatory reaction. This may inhibit hair regrowth and have other negative effects.
PRPHAIRMD.COM