Help!

My baby is 6 months old, I left him with his great grandmother (my only choice, not too thrilled about it) today around 1:30, then returned home at 8:30. He has this little spot by his mouth. The picture of him sitting was before I left today, and the one below is of the spot. After I ate dinner I took him to my room to feed, and as soon as he touched my breast with his mouth, he dry heaved and started to throw up. He hasn’t thrown up since, but he also doesn’t have a fever. Just the spot. Should I stop being a worry wart? Or be on the lookout for something else? I’m just so paranoid with RSV being shoved down my throat, I don’t want anything to happen to my booger-butt.🥺🥺🥺