Are hard lumps and bumps directly under the chin normal following submental lipo? (photos)

It is not unusual to have some temporary firmness and lumps after submental liposuction.  Swelling normally should be improving by 10 days after surgery though.  It may be best for you to contact your surgeon so that you can be evaluated in person.  Your surgeon should also be able to determine if your compression garment needs to be tighter and can should you how to tighten it if needed.  

Patients with questions and concerns about their chin lipo healing process should address those concerns with the surgeon that performed the operation, ideally during a follow up consultation

There can be some firmness or lumpiness after chin liposuction secondary to inflammation and swelling. However it is hard to judge the cause for it based on the photographs. I would recommend you closely follow-up with the surgeon who perform the procedure to track your recovery process.