Blotchy rash on baby’s forehead

My son is 8 months. This morning he woke up with this blotchy rash all over his forehead. We can’t get into the doctor until next week so I’m wondering to see if anyone’s seen anything like this.

We went to the lake yesterday and had a beach day. He had on sunscreen of course and got sand and lake water all over him playing in the water. I did give him a bath last night to wash it all off, though.

He’s acting completely normal. No fever or anything else. And it’s only on his forehead.

It’s not as red as he’s been up longer just like light pink.