My female jack russel has been licking her genitals and under her tail for the past 2 days as well as dragging her bottom along the ground. She is red and raw only in these areas. What could it be and howhow can I treat this?

Best to have this checked by your veterinarian.  She could have an impacted anal gland, a urinary tract infection or even allergies to name a few issues that this could be related to.  Your veterinarian will be able to properly diagnose and treat the problem.  Good luck.