You can't.
How can I grow 10 cm (4 inches) in 2 months?
It depends how old you are ! If you're more than 19 or 20 all you can do is to grow up almost 3 or 4 Cms ! If you're under 18 or 17 you can, but you have to work hard and do a lot of sports such as basketball and vollyball and you should drink a lot of milk ..!
The average rate of hair growth is 1/2 inch per month. There are products on the market that are focused on promoting hair growth and combating hair loss. Biotin is very popular for expediting hair growth but there are many other vitamins, minerals, and herbs that have been proven to accelerate hair growth. B-vitamins 1, 2 & 6, vitamins A & C, Pantothenic acid, Saw Palmetto and Pygeum Africanum have all been proven very effective in expediting hair growth and combating hair loss. HairXT100 contains and all natural blend of these and more and has been proven to make hair grow faster. Hope this helps!