Rather than popping up yet another screen that you can only click “ok” on, at the end of challenges, take the player directly back to the Adventure screen, as per screenshot.
Then animate the XP amount above each character.
Also if you have the character’s XP progress bar under or above each character on this screen, we wouldn’t need to go into the character screen to find out how much more XP is required to the next level. It would be nicely summarised here. Saving time and clicks.
You can reuse the level increase animation, used at the end of challenges here, as the XP value flies and fades above each character’s head.
Ideally if you are using a MVC or MVVM system, moving the UI elements to this screen shouldn’t be too big a job (I hope).