The infection is contagious until the bumps are gone. The time from exposure to the virus until the bumps appear usually is 2 to 7 weeks, but it can take up to 6 months. To prevent molluscum contagiosum from spreading: 1  Try not to scratch. 2  Put a piece of tape or a bandage over the bumps. 3  Do not share towels or washcloths. 4  If the bumps are on your face, don't shave. 5  If the bumps are in your genital area, avoid sexual contact.