I'm a 21 yr old male.  When I was 18 yrs old, I observed a slightly
receded hairline though otherwise I had a dense hair.  I bought the
then widely advertised 'Helsinki formula' and used it for over 2
months.  All through those 2 months, I shampooed my head with that
damned thing everyday, and did not apply oil.  My head was left dry
all time and exposed to sun's heat without oil.  And then there was
the possible chemical damaage due to the shampoo.  Then I started to
lose hair copiously and went almost totally bald.
   Much later only did I realize that this product was a fradulent one
and that it had been banned by the FDA.  Perhaps nobody banned it in
my country, India.
   I wonder what I should do to reverse the tragedy.  None of the
products for baldness like Propecia, Rogaine, Thymuskin, etc are
designed to cure the sort of problem I have brought upon myself.  My
problem is not Male Pattern Baldness (or rather, the slightly receded
hairline I mentioned before alone might have been due to that) but
baldness due to the abuse of hair.  I want to know what treatment I
should undergo to get back a full head of hair.

Wow, what a horrible experience!

I wouldn't know what to do but what a lesson for other folk.

See a dermatologist.  They deal with skin and skin structure [hair and
nail] problems. They may do a biopsy to actually look at the skin
structure under a microscope. If you have scarring, it's a problem.
The hair follicles may have been destroyed. That's unlikely. If not,
time will let the normal follicles start working again. If not, then
Rogaine, etc. are your next step vs transplant surgery.

Bill