I am 18 and until 17 my nose was normal 100%. Now the dorsal hump won't STOP growing and it has changed drastically. Why????

In some people facial growth, and thus nasal growth, continues into their early twenties.  Thus, it may be normal for you that you hump is still growing.

 The dorsal hump is composed of both bone and cartilage and is usually quit growing by age 18. Repetitive trauma to the nose can cause the  the bump to grow bigger due to the fact that bone and cartilage is living tissue and is not static. A rhinoplasty procedure can accomplish shaving down the dorsal hump. For many examples, please see the link below

The appearance of your nose should stabilize by your early 20s.  A rhinoplasty procedure may be an option to correct the dorsal hump.  I wish you the best of luck. Dr. Michael Omidi.An in-person exam with a board-certified plastic surgeon is the best way to assess your needs and provide true medical advice.