You might want to try SebaMed baby product for body, lotion, shampoo. It can be due to weather that baby's skin dry. Or you can also try baby powder lotion from Kodomo. In hot weather you can use loose clothes or material like bamboo fiber/max kool. Also if you are using swaddle try to use the linen type of swaddle. I link my previous post here for ur reference https://community.theasianparent.com/q/sharing-few-materialbrand-suitable-nb-if-keen-purchase-esp-first-time-mu/4483572?d=android&ct=q&share=true
could be baby is feeling warm from swaddle. try turning on aircon to see if it helps? my LO had some rashes appearing ytd morning. started turning on the aircon and the rashes are disappearing