What should I do if I forgot to dry fries before baking?

Bake them anyway and accept that they might not be quite as good as they would otherwise be. A little extra moisture won't be fatal, and there's nothing you can easily do now. You could try patting them with a paper towel but it's likely to remove the seasoning more than it removes water.

You can still attempt to dry them with a hair dryer. This may sound weird to some people, but it's a thing, and I've done this once or twice when I'm having trouble drying foods.

_Source

To avoid oil or seasoning from flying off of your fries, I recommend using the lowest setting on your hairdryer, or keep it a fair distance away from the fries when drying them.