A short chin can mean the chin sits too close to the lower lip, or that the lower third of the face looks compressed. Lengthening addresses the vertical dimension, which is different from adding projection. Thinking that choice through, and asking the right questions, may lower the chance of needing a correction later.
Vertical length versus projection
Before comparing methods, ask the surgeon which dimension is the problem for your face. A plan built for projection may not change length, and the reverse is also true. Ask to see how the surgeon will show you the planned change, such as marked photos or a simulation, so that both of you are describing the same goal.
Look at the whole face
Ask whether a change to the chin will be planned alongside the cheeks and jaw. Read the Cleveland Clinic page on genioplasty and chin augmentation, covering surgery and recovery before you ask which routes suit a short chin.
Options to ask about
The main routes include implants, filler and bone-based surgery. Ask the surgeon which of these suits a short chin in your case and why. Ask what the correction would involve if the result were not what you wanted.
Reversible and less reversible choices
Ask which parts of the plan can be adjusted afterward and which cannot. Ask how that affects your options for a correction.
Nutrition and the surgeon's pre-op instructions
Ask about preparation too. A review of nutritional status before cosmetic surgery discusses preparing patients for cosmetic surgery. Ask your surgeon what they want you to do before surgery, and follow it.
Length or projection: settle it first
Decide first whether you need length or projection. Ask for a visual plan, ask which choices can be adjusted later, and ask what your preparation should be. Then compare the answers from more than one consultation before you commit.