Advice on this growth?

One of my budgies has recently been holding his wing low and not flying aswell as he could for me to go into the aviary this morning to find he had knocked out a blood feather upon checking him i noticed this yellowish blackish lump forming at top of his wing im unsure what this is but i think maybe a feather cyst?? Im looking for advice on what it is and any treatments i maybe able to do myself or straight to a vet, i dont know his background as was taken from another bird keepers aviary and up until recently i never noticed this. The image should have attached any advice is appreciated. Many thanks and happy new year to all the birdy keepers out there.

Yuck, that looks like something nasty got into a bloodfeather and went al pus-filled-surprise from there.

(Diagnosing from a single picture is like shooting at musquitoos in the dark, one can always claim victorie ;P)

I would get him to a CAV- it does not only look nasty, it is probably quite painfull as well.
(there are a few things you could try if you were in the middle of nowhere of course, but if you can reach a good certified birdy doctor - just go there!)

yucky ditto! No advice other than vet visit. I second it that is painful for the burdie...

Hello yes isnt very nice the wee one doesnt seem overly sore with it more so the blood feathers making him ouchie but it seems to be affecting his flight a bit with a droping wing to the point he knocked out a couple of blood feathers in what i assume was a night fright in the aviary the lumpy parts are not connected nor anything to do with the blood feathers is all seperate from reasearch ive done the outcome seems to be leaning towards a feather cyst like ingrown hairs for us, there is multiple advice and remidies you can try at home but think a trip to the vets is best but id rather not risk the bird that size being put to sleep to remove it as ive lost many birds due to anesthesia so think other option is to lance it and attempt to get the keratin and affected feathers out but by no means iam willing to attempt this myself but i have seen other breeders do this with ease but i need to know what it is before anything further i shall try salt baths etc and adding things to diet that have been mentioned in reasearch and hopefully it goes away on its own which can happen from what ive read but must take what the internet calls truth with a pinch of salt alot biased views online. Just want my wee birdy all better and back out to the aviary missing his birdy pals. Shall keep a eye on him over next couple of days and see how he goes i shall try to attach more photos to help get further advice if anyone on this forum is familar with this issue. Many thanks everyone much appreciated.