Hi.. Welcome to HEALTHCARE MAGIC.. As per your complain it seems that you have a dental abscess formation that is due to pus accumulation below the root tips of tooth leading to pressure over the nerves and causing severe pain.. As Root Canal Treatment is being done, gradually the pus will drain off and infection will subside leading to relieve from pain and swelling.. As far as soft green stools are concerned they can be due to side effect of the antibiotics that you are being given to reduce tooth infection.. This happens because the antibiotics disrupts the good bacteria present in intestines along with harmful bacteria and it leads to disturbances in the complex functioning of intestines like Digestion and Absorption and it leads to diarrhea.. It is however temporary and resolves as the antibiotic intake is stopped.. You can consult your treating physician if the symptoms are severe.. As of now, till you are on medication you should take empty stomach Pantoprazole or Omeprazole.. Take Loperamide to control loose motions.. Drink plenty of oral rehydration solution.. Take more of yoghurt, rice, banana and cereals in diet.. If still doesn t improve consult a physician and get evaluated and proper examination has to be done to rule out stomach related infection.. Hope this helps.. Regards..