Although the best course is, indeed, take a rest and give time for the skin to develop callouses to avoid blisters. But if you really can't avoid playing (i.e. you're a professional musician), taking proper care of the blisters and sealing them with super glue (or just protect the skin from the burst of the strings) really works.
But I repeat: do it as a last measure only. Health issues (even minimal ones like aching skin on the fingers due to playing) are not a laughing matter.. and Internet shouldn't be the preferred health consultant