Laser hair removal. My hair has grown back thicker and denser

It may be that the new hair was in a different growth phase. Typically, if it is darker and thicker, then it should actually respond even better to subsequent treatments. It usually takes multiple treatments to achieve permanent hair reduction.

It is too soon to have results with laser hair removal. It will take a series of treatments. I typically have patients do every 4 weeks for the first 3 times and then every 4-6 weeks for 3 times after. See an expert in laser hair removal for best results. Best, Dr. Emer

most people need multiple treatment and need right setting for their skin. If you think you have more hair ask to talk to supervising doctor. They might want to change setting. Paradoxical hair growth is seen more in middle eastern people but it is exremely rare. My guess is that you need more sessions with adjustment of setting but of course your docotr is the only one who evaluated you clinically and can give appropriate consult. Make sure they are a high volume place that you go to. 

Treating very fine hair is tough to get good results, particularly in darker skin types. If the energies are low, the risk is higher for paradoxical hair growth. I don't think that your hair will go back to its original state. If indeed it is thicker, it might be possible with higher fluence to treat the hair now.