Dysport 100 units injected between my eyebrows and for crows feet on May 1st. Feel like it's wearing off already. Normal?

Based on the dose you were given it would be uncommon for Dysport to already be wearing off. Typically neuromodulators' effects fade gradually over three to four months. I encourage you to return to your injector for an evaluation or if you prefer, visit another injector for a second opinion.

This isn't typical, but you could have had initial swelling impacting your results. I recommend following up with your injector. If necessary, a touch-up of Dysport may give improvement. Hope this helps. 

It would be helpful to examine you to give you the best advice as to why your Dysport may be wearing off 3 weeks after you had it done.  For most people, the effect should last at least 2-3 months and for some it can last as long as 6 months.  There are a couple of reasons for why yours may be wearing off so fast.  First, it is possible that not enough Dysport was used.  100 units split between two areas should give you a result, but I would more likely use 120 units split between the frown and the crow's feet.  Some people do require more than usual to obtain the desired effect.  Second, it is possible the placement of the injections could affect the outcome.  Without knowing exactly where your injections were placed, it is impossible to determine if this might be a cause or not.