How can I make my hair grow faster?

I am a guy and my school thought that I hacked their system but I didn't do anything, they sent me to alternative campus and got my long hair shaven off to bald then got out of it in 2 days later because my parents contacted the school board, how can I get my hair back to normal in 4 months? It took me like 2 years to grow to my shoulder. How do I speed it up? Any way to do it? Thanks.