Dear Skin24, Bellafill is idea for shallow acne scars and to anticipate a 50% improvement is actually quite realistic. The risks involved with any filler include pain and swelling at the site, but those are quite temporary. Lumpiness is technique-driven and is reduced by going to an experienced injector, particularly when using the cannula technique. Of course, vascular occlusion is also a risk, but once again is reduced using the cannula technique rather than a straight needle technique. Granuloma formation used to be an issue, but we are now on the third generation of this product and the size, shape, and molecular charges have reduced this to under 1% now. I hope this has been helpful to you. Robert D. Wilcox, M.D.