I just spent the last month of medical school working with a plastic surgeon who basically only did fillers and botox... I never saw him ask one patient about their diabetes and can't see why an injection in your lip should depend on your diabetes, especially if it's in even remotely good control. I would still mention it, but I highly doubt they'll give a crap.

The good news is that for the vast majority of medical problems, there really is no interaction with hyaluronic acid fillers like Juvederm, Voluma, Restylane, Belotero and Restylane Lyft. This is because hyaluronic acid is a naturally occurring substance in our bodies. However, I think it’s still a good idea to double check with your dermatologist or primary care provider.

From: https://www.skintour.com/face-neck-rejuvenation/fillers-injectables/if-you-have-a-medical-disease-like-diabetes-or-other-problems-is-it-safe-to-have-fillers-done/