Hair transplant and Botox?

You should be able to undergo botox injections right away. It should not affect your transplant and the transplant should not affect it. Of course discuss your transplant with the doctor injecting the botox. Incidentally, there are studies looking into the role of botox in hair restoration.

If you want to have Botox treatment to your forehead a month after surgery (when everything has healed), there should be no issue.  However it is best to always check with your doctor.

After the transplant your forehead may develop some swelling that eventually gets pulled down your face typically over the first week. It's not obvious in everyone and usually depends on how strong your immune response is during the heaing process and how much fluid (anesthetics/saline) was injected during the procedure. Because of this fluid traveling down your face, you don't want to get Botox until this process ha stopped. You run the risk of moving the Botox into area that you didn't intend it to be. For that reason I recommend at least 14 days after surgery before getting Botox.