In my opinion you should follow JSmith's advice from the last thread and start using Minoxidil, maybe Nizoral 2% shampoo with ketoconazole twice or thrice a week if you want to. You look much better with this haircut than how you looked in the last thread. You could get a fade on the sides and grow it longer on top, going for a crew cut. The short sides with a fade and longer top'll give an illusion of density, or you could go for a caesar haircut with a forward fringe, or comb it forward like a surfer. I'd avoid any hairstyles that require lots of gel or a blowdryier, and I'd go for styling wax or pomade instead of gel if I were you. You'd have to wait till you're 18 or 19 at least to start taking something like Finasteride because DHT is important at your age and you could end up with some severe endocrine issues if you'd start taking it now, plus no decent doctor would give you a prescription.
I'd suggest looking at your parents' family for balding patterns, thyroid issues or hormonal imbalances because you've got some heavy recession (Norwood 2-2.5) for a 15 year old kid (Damn, I'm eight years older than you and I'm already speaking like an old man lol) and it looked like a NW1-1.5 two years ago. So it went up by 1 in two years. Some meds for acne or antidepressants like SSRI's can cause premature hairloss too. You could schedule an appointment with an endocrinologist if there's any history of thyroid problems or hormonal imbalances in your family.
