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?

this is good, it means you will get a better outcome from the treatment.  Massage and RF treatments like exilis and venus legacy make this improve more quickly.  Best, Dr. Emer.

Thank you for sharing your question and congratulations on your Kybella treatments.  Once injected Kybella damages the fat cell's walls allowing for the body's immune system to clear the fat to leave you with a smoother, sharper neck contour.  Small bumps are the result of the fat being damaged by the treatment and is not uncommon.  These will gradually soften and disappear in the 4-6 weeks after treatment.  Hope this helps.

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.