How to tighten skin after sculptra injections?

I
often use either Ultherapy or ThermiLift before facial sculpting with
Sculptra. Both of these therapies tighten the skin by heating and
contracting the underlying collagen. They also stimulate the
production of new collagen, as does Sculptra, which makes the skin
more resilient and supple. Using these therapies in combination
creates very natural-looking, rejuvenating and long-lasting results.
If you’ve already had Sculptra, you should wait 6 – 8 weeks after
your last session, so the results of your Sculptra are visible before
having your tightening procedure. Please find a board-certified
dermatologist to find out how to get the most out of your Sculptra
treatment. 

There are many options out there that improve skin appearance, wrinkles and tighten skin. It is hard to opinion on what is the best treatment wince it varies from patient to patient and their condition. It would be easier to narrow down options if you provided picture. You may look into Syneron Profound System that encourages collagen production together with elastin and hyaluronic acid. Moreover, there are lasers, that can be combined with other treatments such as microneedling, microdermabrasion, chemical peels, etc. Best of luck!

Generally, if a patient has come for a rejuvenation and one of the issues is lax skin, I will do a skin-tightening session with either Thermage or Ultherapy before proceeding to facial sculpting with Sculptra and/or Voluma. It's perfectly fine to do it afterward, too.
Lasers not only tighten the skin, but stimulate the production of new collagen, which increases the skin's quality over the long term. This combination of facial fillers with lasers is so rejuvenating many patients feel like they've had a nonsurgical facelift. Sculptra lasts for up to 2 years. Voluma will last about 18 months. Laser therapy should be done every year to maintain your skin's resilience and plumpness. Please see a board-certified dermatologist to tighten your skin with laser therapy.