Can someone tell me how long will it take for a cocaine user to show brain and nose tissue damage?

Many variables: Injury to the nasal passages from 'snorthing' will depend on frequency of use, with what the Cocaine was cut and the health of the tissue in the nose. The irritation and erosion is visible. The brain effect is not visible and totally unpredictable. Amount and time of exposure are the critical factors that turn off the brain factory that makes dopamine. Once closed we do not know how to restart.