There's absolutely NO WAY to diagnose what type of parasitic infection he has without a Veterinarian taking a simple scraping of the area and looking at it under a microscope (Yes, your Budgie is a male, by the way...If you treat a tiny little Budgie with Ivermectin, which is extremely toxic if applied topically by the way, assuming he has Scaly Face Mites and he doesn't, then you're putting him at extreme risk...When a bird needs to be treated with Ivermectin for a parasite such as Scaly Face Mites, the Avian Vet with give the bird an INJECTION of Ivermectin, in the proper dose based on the bird's weight, and NOT apply the Ivermectin topically, the way that you would, because Ivermectin is so very toxic to birds and should not be applied topically to them EVER...It's not like treating a larger animal like a dog, cat, or even a rabbit, etc. with Ivermectin drops, spray, etc. If you spray Ivermectin on your Budgie you can so easily kill him with it because you have no idea how much of the poison is going to seep into their bloodstream through their skin...That's why you MUST get your bird to a proper Avian Vet so the correct dosage of Ivermectin can be administered through an injection, once is all it takes, and that's only IF it's actually Scaly Face Mites, which no one can diagnose this way..
There are several different types of parasites, and several different types of mites that look this way, Scaly Face is only one of them, and they all require different treatments.
Again, you just CANNOT go ahead and buy Ivermectin on your own and apply it topically to such a small bird, whether it be a spray, drops, etc., doesn't matter, you have no way of knowing whether you're overdosing/poisoning your little tiny bird. Ivermectin MUST be given to ALL BIRDS by injection only, in a metered-dose. You'll very likely poison and kill you Budgie if you just spray/apply topical poisons to him, he's just too small...Even a Cockatoo is too small to apply Ivermectin to topically, they get injections too, any bird does, because that's just how deadly it is...And it's the only thing that will treat Scaly Face Mites, if that's what it is...
So please, get your Budgie to an Avian or even an Exotic's Vet as soon as possible, because if it is a destructive mite like Scaly Face, it's going to start causing permanent deformities to his beak and face...But please don't risk poisoning him topically, as it only takes a tiny little bit too much of Ivermectin on his skin and he'll die...