My first thought with a droopy wing, and the wet weather we have had here makes me think of botulism. Where are you located and what is your weather like? Here is a thread on botulism, with pictures.
https://www.backyardchickens.com/forum/viewtopic.php?id=219553
We really need more information. Can you answer these questions ...
Give us the following information. The more you tell us, the better we will be able to help you.
1) What type of bird , age and weight.
2) What is the behavior, exactly.
3) How long has the bird been exhibiting symptoms?
4) Is there any bleeding, injury, broken bones or other sign of trauma.
5) What happened, if anything that you know of, that may have caused the situation.
6) What has the bird been eating and drinking, if at all.
7) How does the poop look? Normal? Bloody? Runny? etc.
8) What has been the treatment you have administered so far?
9 ) What is your intent as far as treatment? For example, do you want to treat completely yourself, or do you need help in stabilizing the bird til you can get to a vet?
10) If you have a picture of the wound or condition, please post it. It may help.
11) Describe the housing in use. How many bird in what size of area.
12) What kind of bedding do you use?
13) Have you wormed your bird lately?
14) Have you checked your bird over for lice and/or mites?
15) Lift your bird, hold it. Does it feel heavy or light weight?