If androgenetic aloepecia was triggered due to straightening will hair that falls grow back on its own withought any treatment?

I got my hair straightened a year back..the chemical was left on for 25 minutes more than the max limit..now the new growth on the back is very thin.i had thick hair before the relaxer..the hair on the top of my head is the same density as before..what causes thinning and will it get its thickness back over time if supplements are taken? If androgenetic aloepecia was triggered will hair that has fallen grow back on its own withought any treatment?