I have developed brown spots that look like dead skin on my left hand near my knuckles. i'm freaked out. please help.

Doctor appointment: Without a detailed history plus a photograph or a more detailed description, it is hard to make a diagnosis. I would encourage you to make an appointment with a family practice doctor or a dermatologist. At your young age, I would not generally think that you have a serious skin condition. The unknown is always scary. Try to call for an appointment tomorrow.