Recently, a number of users of the Apple Watch Series 12 and Apple Watch Ultra 4 have reported experiencing skin irritation, including redness and a burning sensation, at the points where their wrists come into contact with the sensors after donning these latest models. Much of this feedback has been shared on forums and the Reddit community, with users highlighting that the problems are mainly centered around the sensor area located on the back of the watches. It's worth noting that the Apple Watch Series 12 and Ultra 4 boast upgraded health sensors. Specifically, the heart rate monitoring frequency has been enhanced to once every 5 seconds, the contact area of the ECG electrodes has been enlarged, the photodiodes have been rearranged in a circular formation, and larger green LED lights have been incorporated. Some users speculate that these sensor modifications could be contributing to the skin irritation, although there is currently no concrete evidence to establish a direct link. Apple has officially responded, stating that skin irritation may stem from an improper fit of the watch band, skin allergies, or prolonged exposure of the skin to irritants such as sweat and soap. They advise users to maintain cleanliness and dryness of their watches, bands, and skin to mitigate any potential discomfort.