I am no expert, but it looks to me like he bruised his nose. The biggest immediate concern I see would be if he is bleeding. Even a small amount of blood loss in a bird is dangerous because they are so small. My best advice is to keep monitoring him, keep him a comfortable temperature (not too cold) and if you are very concerned, you could give him some guardian angel or pedialyte. https://www.talkbudgies.com/article...uardian-angel-pedialyte-pedialyte-recipe.html
Good luck!
Good luck!