Top too moist red velvet cake?!
Serious answers only please.
Leave the foil off of it until you have to frost it. Then apply a thin layer of frosting. This is called a crumb coat. Let dry for about an hour then continue frosting in the usual manner. The crumb coat will catch any crumbs and you won't see them when you frost your cake. You must have put foil on your cakes before they were completely cooled that is why the were too moist on top.
Here is what I would do:
Split the layer into two layers. Frost the bottom layer. Take the top layer and flip it over, moist side-down. Continue to frost as you would normally.
And if I had planned on a two-layer cake, I'd split both layers so I'd end up with a four-layer cake instead of two or three. And it would need more frosting, but the frosting layers would be thinner.
Alternatively, flip the whole cake over and frost the bottom. No one will know the difference.
This is just a suggestion but in theory could work..........try using a Hairdryer? Failing that, if the freezer idea put forward by KT does not work, what about just slicing the top off? You could disguise it with Icing.
Sorry, not wonderful ideas but you only learn by trying and may work. Good Luck x
Freeze it for a while then it should harden off, then you will be able to frost it.