Most acne medications take a few weeks, or even a few months, before there's a noticeable improvement. In fact, some medications might cause acne to get worse before it gets better. Both topical and oral medications need at least a few weeks to start working, since they often require a little time for the antibacterial properties to kill bacteria in the skin, or they take time for the body to "rebalance" its hormones. Don't get discouraged if you don't see an immediate improvement in your skin after starting a new treatment. Talk to a doctor if you're concerned about the effectiveness of your medication.