Lip injections with Juvederm. Dark spots appearing over the course of a year and a half since first injections (Photo)

It's difficult to tell from your pictures. This may be post-inflammatory hyperpigmentation which can be improved with a combination of lasers, Aerolase, microneedling/prp, skin lightening, peels, and skin care. Sun protection is essential. I recommend getting a formal evaluation with a cosmetic dermatologist. Best, Dr. Emer

Hello,It would appear that you have actual freckles/sun spots OR, you may actually be having small areas of "post inflammatory hyperpigmentation" (aka:  PIH) from the minor trauma of the needle insertion sites as seen along the border of the top lip.  Regardless of what the actual condition is or cause - the dark spots are successfully treated with a Q - switched YAG laser.  We often remove sun spots etc. from the lips using this laser with no downtime and only mild discomfort.  Please see the below link for before/after photos of this condition.  In the meantime, please continue to wear sunscreen on the lips or chaptstick with SPF.

Dear natalie dempsey,based on your photo, it does look like freckles which are usually caused by longer sun exposure without appropriate protection. I would suggest you to use sunscreen all the time. And if you are satisfied with the results of Juvederm, you can continue using it. Daniel Barrett, MD, MHA, MS 
Certified, American Board of Plastic Surgery  
Member, Am. Society of Plastic Surgery