When can you get more filler if you feel as though your results are to subtle? Is there a certain waiting period?

From your photo, it appears that you have beautifully shaped lips and are a great candidate for lip augmentation.  Because you're not starting off with a lot of volume loss, lip augmentation, in my experience, can be subtle and many younger patients love their lips right after the first injection when they are still swollen.  In my practice, we schedule a 2 week follow-up appointment to evaluate treatment results, and add more filler if desired.  Another consideration is the type of filler that is used.  In my experience, I tend to use Juvederm when treating older patients for lip "reflation" and Restylane for younger patients looking for "augmentation," because you see a little more swelling and volume with Restylane.  I also have experience with Restylane Silk, as a trainer for the company, and find that to be a great option for more fullness.  If you're being treated by a board certified dermatologist or plastic surgeon  (which I recommend), you should consult with your physician 2 or more weeks after your treatment for specific advice on whether more filler would give you the results you're looking for.

Hi there ~ I think your lips look great!I typically ask my patients to wait at least
two weeks for swelling & any bruising to go down.At that time I will re-evaluate and as long
as there are no contraindications, I am happy to inject more filler for a
fuller look.Call your injector to
schedule a follow up so you can let her or him know that you would like your
lips fuller.Best wishes,Dr. Michelle Spring
Glacier View Plastic Surgery

If you think you need more, it's OK to ask for more.  Swelling is usually gone in 1-2 weeks for more patients, so that's a good time to judge.