Tightness and pressure in forehead and brows 8 weeks after. Could the Botox impact the headaches in some way?

Thank you for your question. I would suggest you discuss with your board certified facial plastic surgeon because it does not seem like the Botox is causing your headache based on the time in between the injections and the start of your headaches. Additionally, Botox is usually used as a treatment for headaches. 
Best wishes,

It is unlikely that the symptoms you describe are from the Botox injections as they didn't begin until 8 weeks after treatment.  Botox is used sometimes to actually treat headaches and migraines.  I would recommend seeing your PCP if the headaches continue.

Thank you for your question. It does not seem as if Botox is causing your headache based on the time in between the injections and the start of your headaches. Botox is typically an effective treatment for headaches/migraines. Follow up with your injector to discuss your options and concerns.

Botox is actually indicated in the treatment of migraine headaches.  That, plus the timing of your headache makes it very unlikely that Botox caused the headache.  Hope it improves, if not, then you should see your family doctor.  Best wishes.  Dr. Fleming

Although Botox can cause and relieve headaches, the timing sounds like your headaches are not caused by Botox injection.