I'm 21 years old, I've smokes for 4 years. There's a white area next to a tooth that is decayed and sharp. Is the white area from the tooth?

Could be. But since you need that broken tooth restored, why not go to the dentist to fix your tooth and have them take a look.
Possibly. Could be pus from the infected tooth. Could be one of the many bacterial, viral, or fungal lesions, could be traumatic injury from the sharp edge. Could be precancerous or cancerous lesion, especially as you smoke. Please see your General Dentist immediately for examination and treatment. Pleas also quit smoking.