Rash help!!!

My son just got over what we thought was a stomach bug that my husband and I both had. He took a couple days longer to feel completely better. His fever got high several times and we had to alternate between Motrin and Tylenol for a couple days just to keep it below 102. I took him to urgent care when it first began because his fever was 103 and they ran a flu, strep, and RSV test all came back negative. So I figured he caught my husbands stomach bug. He’s feeling fine today and no fever at all but he has this rash!? It’s on his forehead, chest/belly, and some on his back. Is this normal after he was sick? Or maybe from his fever? FTM panic mode lol the rash appeared this morning.