Benadryl is always an option for allergic reactions but never give animals medication without discussing it with your vet first. You don't want to give your dogs too much! (For reference, my vet said that in a pinch, Ares at 19 pounds can have one pill and Luna at 10 pounds can have half a pill.)
Unfortunately for Ares and Luna, as each day passed, they were sneezing and reverse sneezing more and more. By last night, I could hear the Ares' congestion as he was laying on me, breathing, and poor Luna would have reverse sneezing fits that would leave her literally gasping for air.
My amazing vet managed to get me in before I had to work today to see someone today to give them relief. It will take 24-48 hours for the medicine to work its magic on them but at least we've started the clock on it.
A quick note on reverse sneezing:
it's mostly a squishy faced dog thing. One video I saw on YouTube said that it is a result of an allergic reaction to something (in Ares' and Luna's case, they were having respiratory problems from the pollen). There isn't really anything you can do to stop your dog from reverse sneezing but there are a couple of things that can help. One is to rub their throat and the other is to hold their nostrils closed. The idea behind these techniques is to make them swallow and calm down. I took a video this morning of Luna's reverse sneezing fit. She usually does it for quite awhile and like I said above, she is gasping for air when it is over. It's a scary thing to see but don't be worried if it happens.