13cm erect, 5cm when flaccid - is penis filler okay to increase my length & girth?

I have written a few papers about penis enlargement, augmentation phalloplasty, and evidence-based outcomes. Safety is always the priority. Here are some links to the papers:
Penis enlargement surgery can offer modest improvements in both length and girth, but there are risks and limitations that should be carefully considered. Always go to an experienced provider. Complications can be devastating.
Lengthening Surgery: The most common method involves cutting the suspensory ligament that attaches the penis to the pubic bone, which can result in an increase of about 1 inch in flaccid length. However, this may not significantly affect erect length. Additionally, some men experience a "drooping" effect where the penis no longer rises in erection, but instead points downward.
Girth Enhancement: This can be achieved through fat grafting (using the patient’s own fat) or the insertion of dermal fillers or collagen-based materials. These techniques can add circumference, though fat grafts may have issues with uneven absorption, and synthetic fillers can lead to complications like infection, ulceration, or extrusion. The use of Alloderm (a type of cadaveric tissue) has been controversial due to risks of tissue reabsorption or complications.
Minimally Invasive Alternatives: Non-surgical treatments, like platelet-rich plasma (PRP) injections or fillers, are also options for improving penis girth and overall appearance. These methods generally have shorter recovery times and lower complication risks compared to surgery. Fillers tend to increase girth, and increase flaccid length minimally due to the extra weight.
While surgery can lead to some visible improvements, the results may not meet all expectations, and the risks of complications are significant. For those seeking a modest increase in size, non-surgical options may offer safer alternatives. Consulting with an experienced surgeon is essential to determine the best course of action.
Krishna Vyas, MD, PhD, MHSHarvard, Hopkins, & Mayo Clinic Trained Aesthetic Plastic SurgeonNew York, New York

Penis fillers such as bellafill, radiesse, voluma stimulate collagen production and volumize the penis. The result is an increase in penile girth but none of the bio-stimulator fillers mentioned above increase penile length.

The Girth Shot that I perform will certainly increase girth in your situation, but it doesn't have any significant effect on length when erect. It does increase the length somewhat while flaccid, due to the filler having a little weight to it.