Same idea as immunotherapy shots or sublingual drops.

Whether it’s actually local, and if the allergens are actually concentrated enough to make any difference, is a very different question. Set of questions.

Don’t forget this one: Is it actually honey? Honey flavored corn syrup doesn’t help.

I’m guessing this is a US thing? At least I’ve never heard of it before as a european and I’m pretty sure it wouldn’t be allowed to be sold as honey here