It's been 4 weeks since my 2nd Kybella treatment, and there are a lot of small, hard lumps under my chin. Is this normal?

These hard nodules are fairly common after Kybella treatment and actually are a good sign that your fat cells have been damaged by the chemical in Kybella. The nodules are small areas of fat that have been damaged and hardened. They will soften and reabsorb usually by 8 weeks after treatment. 

One common side-effect of Kybella is lumps or bumps in the treatment area. These nodules should dissolve over time, usually within a few weeks. If these nodules do not dissipate or cause you pain, contact your physician for assistance. Many experienced Kybella providers are waiting longer between injections. Recent data has shown continued improvement past the 4 week point. I have my patients return 6-8 weeks after injection.