I am currently nursing my silkie back from (what I think) is a mild case of wry neck. (She got it after a peck to the head/ear). After not knowing what was up with her for a few days, I decided she was exhibiting symptoms of wry neck. I talked to a friend, who works at a bird rehab center (she is not a vet), and she advised the following.
I got:
From the petco bird section: vita-sol vitamin drops for 5$ (no iron, iron will block absorption of other vitamins) and exact for 5$ (a powdery gruel used to handfeed baby birds).
From my own medicine cabinet: vitamin e capsules
From a friend (but she got it from the vitamin section of a grocery store): selenium 100 mg powdered capsules
Until recently, my bird has refused to eat or drink, so I've been dripping water on top of her beak, and eventually progressed to egg yolks and yogurt. She reluctantly ate it, more out of a reflex than a desire to eat it. And she ate barely anything. I started mixing in the vitamin drops with the water, and that seemed to help. I also made a mixture of 1/2 a selenium capsule with water and some vitamin e, and tried to get her to get some of that too - she got a tiny bit.
I'm not sure if the drops and vitamins started working, if she started feeling better or what... but yesterday, she seemed to take the food a little bit more willingly. So, I made a mixture of the exact gruel (1.5 teaspoons of the powder with 5-6 teaspoons of water), mixed in half of a selenium capsule, and a vitamin e capsule (they need both together, the selenium helps the bird absorb vitamin e), and a few drops of the vita-sol. (Careful not to give too much selenium, it can be toxic in high dosages - I read 50 mg was acceptable for a day, my bird is getting maybe 25 mg at most throughout the day.) I mixed it in a shallow dish, held the bird on my lap, and submerged the tip of her beak (taking care to avoid her nostrils) into the mixture. She started lapping it up! She took maybe 1 teaspoon, then refused to take any more. So I let her rest. And repeated the process a few hours later - she took another teaspoon. It's very encouraging. She seems to be getting peppier! And it is certainly the most she has eaten at once in the last few days. Too soon to say if it will be totally successful, but so far so good!
My bird didn't have a super visibly twisted neck. But her neck did feel odd, and kinked. She hunkered down in her bedding. And she refused food. If your bird has an inverted head, not sure how you'd have to adjust. Others have posted links that have good info though. Good luck!