Hi.. Can understand your concern.. As per your complain an abscess in the gums can occur due to any injury to the gums by tooth brush bristles or any hard or rough food item or any other thing taken in mouth which accidentally hurt the gums leading to carrying of bacteria in the gums and at times any foreign body can get impacted in the gums leading to infection, inflammation and pus formation and causing GINGIVAL ABSCESS.. An infected tooth can also lead to accumulation of pus outside root tips leading to abscess formation. Taking antibiotics alone can at times be relieving but in some cases and if not relieved professional cleaning of teeth known as scaling is to be done.. In case of infected tooth treatment of tooth may be needed.. Pus is not a toxic product if swallowed but as it contains infectious bacteria in it if the pus enters the stomach it can lead to stomach infection as well as infection in throat.. I would suggest you to complete the antibiotic course and follow up with the doctor as if any treatment will be needed can be done.. Hope your query is solved.. If you find the answer helpful please write a positive review and click on find this answer helpful as a token of appreciation.. Thanks and regards.. Dr.Honey Nandwani Arora.