It's not recommended to drive with a blown head gasket because it can lead to coolant leaking and then cause overheating of your vehicles engine which can then seize the engine up leaving you stranded.
If the head gasket is completely blown then you'll need to replace the head gasket otherwise you'll be looking at a replacement engine.
If the head gasket is slightly leaking then some head gasket sealer can help stop the head gasket from leaking at least for awhile.