The hair cycle normally consists of growing, resting and falling hairs and there is a delicate balance between these stages of hair cycle. Normally hair should re-grow but if it is not happening, you should consider seeing a dermatologist.
Further information is in the following weblink
https://www.aad.org/public/diseases/hair-and-scalp-problems/hair-loss
Next Steps
Start on biotin supplements and food rich in iron content. Use a milder shampoo and consider frequent shampooing and conditioning.
Health Tips
Your dermatologist will decide a treatment plan for you after a consultation.