I had botox 3 days ago and my head is frozen already. Is this normal? If it takes 2 weeks, I'm worried it will spread to my brow

Up to 2 weeks for full effects. Some people feel the effects of a Botox treatment 3 days post treatment and for some it takes 2 weeks. If you feel it within 3 days this doesn't mean it will spread to other areas.

Hello!  Thank you for your question.  It can take up to 7 days for BoTox to take effect.  Often, patients experience effects within 1-3 days.  Your timing is not uncommon.  Best wishes!

It sounds like you are on the path to getting an excellent result! While
Botox starts kicking in around day 2, it typically doesn't reach its
max benefit until around day 14. This is highly variable amongst
patients -- some say they have full effect much earlier -- like yourself! Don't try to
evaluate the results of your injections too soon -- wait the two weeks
and then assess. If you feel you have too little movement or your brow is down too much, then ask
your injector to use less next time. I wish you well!