A "touch up" only 2 weeks later?

I appreciate your concern. Two weeks is the average time it takes to see the full results of Botox injections. Some providers will schedule a follow-up at that time where they can add more Botox if needed, especially if treating you for the first time. However, it is also customary not to charge for the touch-up. If you choose to have additional areas treated at that time, there would be a charge. I would clarify the policy with your provider to put your worries to rest. 

Thanks for your question. It is not unusual for doctors to follow up with patients two weeks after their first Botox treatment to see if the dosing amount was correct. This is the point where the full effects of a Botox treatment is usually seen. If a touch-up is needed, it is typically complimentary. 

At two weeks post injection your final results can be seen.  The physician may be referring to a "follow up" appointment to evaluate your results.  If a touch up is needed it can be done at that time as well.  You may not need any further treatment at that time.