Time minimum between treatments?

Absolutely, you can definitely reach out to your physician to discuss any concerns you may have after your treatment. It's important to remember that results from Juvederm injections can take 1-2 weeks to fully develop. However, if after this period you still don't see any improvement, you should contact your doctor. They can assess the situation and determine if additional treatment is needed.
Remember that everyone's body reacts differently to treatments, so what works well for one person might not work as well for another. Your doctor should be able to guide you on the best course of action.

One of the wonderful benefits of filler is that you can go slowly and build up to the results you are wanting. Yes, you can return to your injector for further product to help you achieve your treatment goals. Be sure you see an experienced injector for optimal results.

As filler integrates into the tissues it can get better i would recommend waiting 4-6 weeks post initial treatment before receiving any more filler. This will give time for the existing filler to settle and integrate into the tissue.

Typically for superficial treatments such as acne scarring you would notice a benefit right away. However inflammation from the procedure can distract you from the results. Either way, a responsible injector will wait 2 weeks before retreating the same area.
You can also try other treatment options such as smooth threads or microneedling (SkinPen proven results for acne scarring)

It’s not at all uncommon to do adjustments with fillers. Most providers do this about two weeks after the initial procedure to let the swelling settle down from the first procedure. The only reason to wait longer would be if there is significant bruising from the first procedure.
Each provider will have their own recommendations and protocols, so I suggest you ask your provider.
I usually have my patients watch during or immediately after I inject a fillers, and we usually talk about the process as we’re doing it, so patience feel happy with the outcome.
Best,
Mats Hagstrom, MD