How can I tighten up loose skin under my chin? (photos)

From the limited photographs, it appears that there is fatty deposits in the neck and loose skin, but that must be confirmed at the time of an examination/ consultation. It's also important to look at the elasticity of the skin and the patient's age. When the skin tone is adequate, a necklift can be performed. When the skin tone is inadequate and loose, then a lower  face and neck lift is required. For more information and many before-and-after examples, please see the link and the video below

So you have two notable reasons, namely, slightly ageing skin and soft tissues under the neck and a weak chin. The two of these together make this sagging much more readily obvious. The options therefore include sucking out any fat using local anaesthetic micro liposuction and augmenting the tip of the chin to create more length to the jawline. This an be done with any filler product non surgically or the fat generated from the liposuction if that is fat that we see. Hope that helps, Adam Goodwin