Fly Issue Etc

I'm having an issue with my momma mare Desire and flies. First of all, the flies LOVE her. She wears a fly mask all day every day and I fly spray her as well, but a week and a half ago or so I noticed she had two little sores on her belly, apparently from the persistently biting flies. I cleaned them up and sprayed Vetericyn on them and they are mostly healed over now but yesterday I noticed that they were both also slightly swollen, and the flies were clustering on them with a vengeance. Less swollen today but looks like one is starting to become raw again, so obviously the flies are just harassing the areas non-stop. The swollen spots aren't hot or painful to her, just ITCHY. I put out an email on my local horse forum to ask people what they might have used in such a case, it being my first horse with any sort of skin sensitivity and heard back from quite a few people who said to put on everything from tea tree oil to Vaseline to MTG. My riding buddy suggested War Paint, which she had put on her mare's belly when a similar issue occurred, minus the swelling. I think I might try War Paint first and go from there. I've heard MTG can be great but is also really smelly and awful, and knowing Sheza filly she will give herself a new hair-do or something equally silly with whatever goop I put on there. The War Paint sounds low profile but (hopefully) effective. We shall see! I am dying to saddle up the mare and really ride her, get her to start losing those pregnancy pounds again but one of the sores is right where the girth runs, so guess I will have to wait to try out the new mohair girth, stick with bareback riding until I get those darn spots resolved.
Blaze and I met our riding buddy C at the lake this morning. We did the loop around the horse camp only out and back instead of a true loop, since the loop itself is very short and still partially underwater! The lake is so high this year, its truly amazing every time I see it. The ride was 10 miles in about 2 1/2 hours, we mosied along at some spots and let them stop at all the water so it was a little slower than I had been riding that ride, but we had some good long trots and it was a fun ride. Blaze seemed downright tired at the end, the last mile or so he started tripping a little and his always-slow walk was at its absolutely old-plug slowest. We are planning to meet C at the lake again Sunday but at another trail head for a longer ride, and as the weather is forecast to continue cooling, it should be a great ride.
I rode Blaze without any wrap or boot on his left hind yesterday morning and today and he didn't hit it at all, it is looking good and finally healing! I'm so happy for him for that to be healing and feeling better and me coz I don't have to stress about it and wrap it constantly anymore! I think I only went through 20 or 30 rolls of vet wrap during that little escapade. Now we know, no hind shoes for Blaze. It all really makes sense now that I bought him with that big ole bump sticking out on his left hind, someone else must have had him shod all the way around and either was fighting it for a long time or just didn't care or notice and let it continue for a long time, since that bump is clearly the spot he interferes when shod and had to take some real banging to become raised like that. Anyhow I am very glad that is all looking better and now just need to resolve the Case of the Itchy Swollen Bites on a Gray Mare.