My 3 month old's neck is constantly wet/damp and red as well. the colour around the redness is different compared to her normal skin. what can i use?

Confusing question: Is the kid just chubby with neck roles that sweat against each other? Is this an isolated issue with a skinny neck ? Infants sweat & expel heat more in their head/neck than their trunk, so this may be a normal variation. You can blow the area dry with a hair dryer on no heat setting & baby powder (no starch) may help. Have her doc evaluate it at the next checkup.

Keep clean and dry: This is a common condition, and if the skin is not infected with any distinct lesions, using a gentle baby soap without fragrance and blotting dry a few times a day may help to soothe the area and to prevent infection.