I read viruses can steal the cell membrane of a cell after it kills it to blend in and not be detected by your body. how does your body then find it?

Temporary housing: A virus does move into a cell and take over its little factory sites to make new virus (not hide). After its presence has destroyed the integrity of that host cell, the cell wall breaks down and all the new viruses enter the blood to find new cells and start over. Your immune system (and fever response) detect the new viruses and work to kill them off.This is considered why your temp fluctuates