So I have a relatively long neck, that sort of is obvious? in appearance I guess and it makes me very aware of its existence haha.
I feel that what really helped me in the long run was using sunscreen everyday, and moisturizing it well (sometimes using a retinol cream) in the evening before bed. Doing this consistently really helped smooth out my skin for me. When I got inconsistent, it showed.
On a side note, as a healthcare professional who has been in a lot of surgeries (and I'm not trying to deter you), since you are young, I think it's best to take your time and think about the potential neck lift in the future.
I understand you say that you don't need one yet, but make sure your really want it and are a good candidate for the procedure when that "yet" time comes. The neck skin is a very thin and delicate skin. A neck lift works best when there is loose or hanging skin. If it's lines you are concerned about, but you have little to no loose skin (even when it's later down the line), the result may not be what you had hope or worth it to you.
But, I'm sure you'll do your research
Get a lot of consultations with Board Certified Plastics surgeons, and make sure they are currently Board Certified. Board Certification is not just a one-and-done license. It has an expiration date. While not required, it is best that it is renewed so that the surgeon is up to date with medical knowledge and research.
Apologies for my spiel on plastics. Again, not trying to deter you, just want to make sure that you really want it and am ready for it if and when you do it.