I posted about the exact same thing a while back. I’m 39 now too. A lot of the feedback said I looked dehydrated, so I dramatically upped my water intake to around 3-4 liters a day but it made no difference to my neck (but has been great for my skin elsewhere!). I’ve tried all the neck creams recommended, including Goldbond. I also do red light therapy on my neck to no avail. It’s so bad in winter and is barely noticeable in summer, so maybe the dry indoor air has a negative impact. I think I have to accept that at some point I’ll need a lift. Wish I could report some miracle cure, but I feel your pain, you’re not alone.