Re entry into HK

I am a South African passport holder, I arrived in HK on the 31st August, but I will be visiting China from the 14th for 15 days only. I entered HK freely and was granted 30 days which ends on the 30th of September. I would like to know if I will be able to re enter HK without an entry permit, or will I have to apply for a tourist entry permit for HK,whilst in China?

Please advise.