Raise in internal body temp?

[NyMe18]

My 6 yo has always been like me - cold. He’s always wanted clothes on and loved co-sleeping close under covers and we’d warm each other up. He’d also occasionally get down to a 35 degree body temp, especially when we had a harder time to get him to eat. During the night he’d also go down to this internal temperature.

But suddenly lately this completely changed. He now acts more like his younger sister and kicks off covers, doesn’t want to wear clothes etc. it is of course fine with me but I can’t help but wonder about this sudden core temperature change which the first few days had me checking him for fevers as he was warmer than I’m used to.

Is it.. common?