why does my beardie suddenly dislike me?

I have a 7 month old boy. He is pretty chill and healthy, and does not mind me at all. Today I took him outside to get some real sun because of tremors from last night (he seems fine now, theres just an impaction issue). The tremors were likely from the enclosure being too hot, which I fixed today.

Today when I took him outside and the sun shone on my face, he suddenly didn't recognize me! I went in for a kiss on the head, and he opened his mouth. He was fine with me prodding him (helping him shed) and my fingers near his face. He didn't look stressed either.
At some point he lot his stress marks and started trying to get away (not sure to get away from me or just wanted to explore) but he definitely did not want my face near his. After I brought him back inside, he went back to normal and accepted some kisses.

Why didn't he like me when we went outside? Not really an urgent question, just a really weird thing.

Has he been outside before? If he’s not used to it, it may have been over stimulating. Either way, he may have thought you were going to eat him. However, opening his mouth is not really aggression. If he puffed his beard and it turned black, that is aggression. If he just opened his mouth it may have been just to regulate temperature.

Also, don’t pick off his shed!! I know it’s tempting, but it can lead to infection. If you want to help him, just give him a bath and let him soak. You can use a soft toothbrush to gently scrub him when he’s in the bath, too.