So a question for parents.?

Last summer, I caught my 14 yr old daughter smoking..I punished her harshly to get the message thru. Her and I made a deal about a month ago, stating if i pierced her nose, she would not touch pot at all until she was at least 18. She vowed this. So i pierced her nose. So today, i was looking for something in her closet and I found 5 cigarettes that smelled fresh. I am a smoker so I compared the cigarettes I found to one of mine. I also found a small amount of weed wrapped in foil. It looked like it had been there in foil for a while. Obv. I will confront her. But how should I handle it after..