Are these necklines caused by fats and over weighting?

Hi doc, I'm 20 yrs old but I look like 30 because of these lines on my neck and I feel bad about it. I really want to get rid of these as fast as I can. I started having these lines since I gain weight and having more fats. I always think that going to fitness gym and doing exercise to reduce my body and neck fats can help to erase all of these. Tell me doc if that could help