Hi!asmaa,
Welcome To HealthcareMagic forum,

Asmaa, probably when you started loosing hair it was some kind of irritant reaction to begin with ,as you said you had used some caustic substance .Later on it was not irritant reaction ,and you continued to loose hair.Another important point is -how may hairs are you loosing per day now.If it is only few strands ,then it is completely normal.
In females the most common cause of hair loss is –iron deficiency, hormonal imbalance, thyroid problem, stress, lack of sleep, familial ,or use of chemical on scalp ,procedures like perming or straightening etc. Other rare causes are zn & copper def. One has to find the exact cause of hair loss and treat. In females there are various patterns of hair loss,which can be judged clinically by a dermatologist. As you have mentioned its the frontal area getting involved that would mean a hormonal patter of hair loss.As you mentioned ,your Hb and s.testosteron is normal ,then probably its not hormonal .But there are other test also which needs to be done to rule out hormonal hair loss and even an ultra sound if necessary to rule out PCOD.This usually seen in obese patient with irregular periods.
Other simple test which we do are hair pull test and trichogram to diagnose which type of hair loss is there.
After proper diagnosis you can start with topical preparations like Minoxidil 2%-5% applied twice daily on scalp along with tab biotin one daily.Other hormonal medicines are also available if needed.
Along with this we have US FDA approved laser also to stop hair loss and promote growth.Its called hair max laser.Then we also do meso therapy ,where we give tiny injection on scalp to prevent hair loss.
Improve your diet with green leafy veg, fresh fruits, plenty of water, sprouts ,pulses, high protein diet, avoid items with high sugar content like sweets & chocolates, less of Chinese foods, less of pizza & burgers ,more of milk & ghee, dry fruits . Good sleep also has a important role to play .
For detail information you can visit my website www.skinhairclinic.com.(hair transplantation section) .

I hope this would help you understand about your condition.If you have any further questions,please write back to us.

Take care,
Dr.Chawda