Dupixent wearing off before next dose?

Hi! I hope someone can answer. I have been on dupixent going on 4 months (17 weeks) and I find that my skin will start to flare 4-5 days before my next injection! Is this normal? It’s like my dose doesn’t last the full two week. It makes me question if the medication is even working given the fact that I have to reach for creams more and I get a little more itchy before my 2 week mark for the next shot! Has anyone experienced this?