I was recently injected with Xeomin. I am adding the pictures of my results after 3 weeks. (photos)

Xeomin is a newer neurotoxin made by a company called Merz. In my experience, the results are very similar to its competitors, Botox and Dysport. In the glabellar area (the 11s), these products are usually excellent at relaxing the muscles and removing the lines that come from brow movement. To this end it can lead to a more youthful brow appearance.That being said, there are a few reasons why people do not get the results from these products. The first is that some people need slightly higher doses of the product to get the desired effect. While there are suggested dosing regimens for these products, some people fall outside those suggested amounts and hence the need to work with the physician to find a dose regimen that works for you. The second reason is if the injections did not effectively put the product into the muscle. Doing the injections in another plane of tissue can make the products less effective. Third, sometimes one needs to wait longer to see the benefits, though in your case 3 weeks is usually sufficient to see the desired result. Finally, I have seen cases where some people tend to do better with some neurotoxins than others in terms of getting the desired outcome. To this end, we sometimes try different products on people to try and find what works best for them.In terms of fillers, I am not very enthusiastic about injecting fillers in this region. I do not feel it offers a very good cosmetic result given the hyperdynamic nature of the muscles in this area, and there is the hypothetical risk of having retrograde movement of the fillers into the blood supply near the eye. In our clinic we offer laser resurfacing of this region, isolated nerve ablation, and fat transfer all of which I feel work better than fillers for complementing neurotoxins.  

Most likely explanation is that you have static wrinkles which means the wrinkles are visible whether you move your facial muscles or not, as opposed to dynamic wrinkles which occur only when you move your facial muscles. 
Dynamic wrinkles respond to neurotoxins like Botox/Xeomin/Dysport very well. While static wrinkles do not.
I think your wrinkles are mostly of the static variety, and that is why your wrinkles are still visible despite repeated treatments.
Second possibility is you may still need more neurotoxins.

Each patient is unique when it comes to the number of units needed to achieve a desired result with neuromodulator medications like Xeomin. In most cases, more units will help to correct an inadequate result. I do find that patients tend to get better results over time, and that patients with very strong muscles may need either more units per treatment session or more frequent dosing to achieve the desired result. I think that patients tend to "un-learn" the facial expressions causing the wrinkles and the skin relaxes over time, giving a better result with consistent injections every 3-4 months.Always see an expert physician injector.All the best,