My lip injections are gone after a month every time?

Thank you for your question and I am sorry to hear of your difficulties.  There can be some variability in the duration of fillers that is patient specific, as well as some loss as the swelling of the tissues resolves, but complete absorption should not take place within 2 weeks.  Do you have before and after photos that you would be willing to share?  You may require greater amounts of filler placement to achieve your desired result or perhaps a thicker material such as with Voluma.  Be sure to see a board certified plastic surgeon in consultation

This is a technical error of injection too deeply.  Find another injector.  If indeed it goes away with a new injector, it is the material and your body.