Root canal 3 day ago - on amoxicillin - jaw still numb and tingling - lump inside gum/jaw i press outside and feel serious pain - worried jaw cancer?

Unwarranted Fear: Most likely a serious abscess... that's why you're on antibiotics. Your dentist took radiographs to examine the tooth; bone cancer and cysts look quite different than a dental abscess. Your body has a major, enclosed wound... allow the medications time to work and allow your body time to heal. I'm sure you'll be just fine.

RCT numbness: Teeth that require RCT may have a serious infection that requires multiple visits, continued antibiotic coverage, occasionally soft tissue drainage, and time to heal and resolve. Having said that, in some cases, surgery or even removal of the tooth is required to resolve the infection. No need to worry about cancer! Discuss with your own dentist, perhaps 2nd opinion with Endodontist if an issue.

Root canal: It takes time for an infection to clear. If swelling and pain does not resolve within 5-7 days, call your dentist or see an endodontist. Also, jaw should not still be numb. Call your dentist or see an oral surgeon for a consult/exam.

Paresthesia: related to root canal treatment. Many factors may cause paresthesia after root canal (e.g. injection to the nerve during local anesthesia). Regardless, the paresthesia resolves by itself after approximately 8-10 weeks. If concerned, see your dentist for evaluation.