Is his coloring changing or is his feathers wet?

[Notjomomma]

One of my Budgies Yoshi doesnt show signs he is sick eating, playing, actung normal, poop is fine, cere is not wet. But above his cere is getting a lil darker is it just changing or is it wet, he doesnt let me touch his face yet lol only had him a month. Im attaching a picture to see what you guys think. I APPRECIATE YOU ALL SOO MUCH FOR YOUR HELP!

 

[Mybluebird]

Sometimes budgies rub their heads on a perch which causes that darker appearance. They do that especially when they are getting new head feathers because the pin feathers itch. I can't tell from the picture if Yoshi is getting new feathers. I'll also tag some experts here to give you their advice. @Ripshod @Lady Jane @Lori D Pert @Zara

 

[Ripshod]

How old is Yoshi right now? It does look like his bars are receding so as @Mybluebird suggested it's probably from rubbing.