Translation
All the days he has the mark of being stricken he shall be regarded as unclean for he is unclean; he shall dwell alone; his dwelling shall be outside the camp.
Paraphrase
For as long as he has the outward indications on his skin that he has been struck by God, he must be regarded as being in isolation due to an unacceptable condition before God for indeed he is isolated from God and unacceptable to God while in this condition; he must live alone; he must live where he cannot influence his fellow Israelites with his rebellious attitudes.