This is a difficult question to answer in some respects without actually being able to examine your face. The first thing that I will say about aesthetic surgery, is that your opinion is the only one that truly matters at the end of the day. What I mean is that if you don't think that there is a problem with something on your face, and someone else thinks that it should be changed, then you will likely not be happy after getting it changed.
However if you do have a small chin, and you agree with that and want to change it, then absolutely there are different types of procedures/implants that can be done to give a more pronounced chin. As for whether a chin implant
with improve the sagging of your face...the short answer is probably not. Again I would need to examine your face closely in order to discuss what I thought was going on in terms of the sagging and what different procedures are an option for you. If you truly have sagging, and that is the most worrisome part of your face that you want fixed (and not necessarily your chin), then a face lift
may be a better option for you.
I might add that commonly chin augmentation is done at the time of face lift, but the implant doesn't really address the sagging. It sounds like you need to have a consultation with a facial plastics surgeon
. Hope this helps.