Steph,
I'm so sorry that you and most of all Maddy are having to go through this. And, it always seems to just drag out forever with the hearings and meanwhile, the kids are the ones most upset by it all.
The sunburn is bad - not only painful, but one bad sunburn increases her chance for skin cancer as well. But the fact that he didn't even alert you to it is the most questionable thing. If it was cloudy and he forgot (I'll TRY to give him the benefit of the doubt), then he should have been treating it with lotions and told you about it as soon as she was dropped off.
I went through a divorce and brief custody hearing until both my ex and I stopped the custody battle and settled on joint custody because our main concern was with our DD. Even when we were mad at each other, neither of us would ever do anything to harm or jeopardize her physical and/or mental well-being. We would keep each other informed of every little rashes, illness, cough, nightmares so the other was an informed parent. The fact that your ex doesn't do any of this seems to indicate that Maddy's best interest is not in his heart. I'm SO sorry and hope it works out for you both and SOON!