Sometimes it’s best to fight fire with fire, and that’s the approach doctors are taking against acne, that bane of adolescence, by sending in a relatively inert virus to fight the bacteria responsible for skin blemishes. These viruses are already embedded in pores deep inside the skin and have a natural ability to infect bacterial cells, turning them into virusmaking factories before causing the bacteria to self-destruct. It’s just a matter of boosting their numbers, which researchers say can be done with a topical cream that’s loaded with the viruses. Or they could simply slather the cream with the bacteria-killing agent that the viruses produce. Either way, it could mean welcome clear skin for teens.