I was wondering if smoking weed 4 hours after getting Botox is harmful/dangerous?

While there are no FDA clinical trials looking specifically at this question, there should be no contraindications to smoking marijuana after or before having Botox treatments.  The mechanisms of action are different.   Seek out a qualified injector though for your treatment to ensure the best results and a 'natural" look.

Smoking pot after Botox will not affect its efficacy. Though legally I obviously cannot encourage you to do this. "This answer has been solicited without seeing this patient and
cannot be held as true medical advice, but only opinion. Seek in-person
treatment with a trained medical professional for appropriate care."