This lemon fruit has lumps

Please provide us your location (country/region or State and county/city)
Thanks. This will help us assign the question to the appropriate specialist.

I live in Cordalba, Queensland, Australia

Hi there, while this pretty far out of my area, I think you are likely dealing with lemon scab, which is not attributed to an insect but a fungal pathogen. This literature states that the disease is common in coastal areas of Australia and when I searched for Cordalba, I saw that your location is coastal. Please see the links to these Australian Extension publications. They give tips for diagnosis and management.

http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0020/138242/managing-lemon-scab-in-citrus.pdf

http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0006/137724/12-lemon-diseases.pdf