Hi.. Welcome to HEALTHCARE MAGIC.. I have gone through your query and can understand your concerns. As per your complain and presentation of symptoms as you have a dental abscess there must be a sinus opening from where the contents of the abscess that is blood and pus had drained.. It is true that in case of long standing infection the infection can enter the blood stream causing generalized infection which can cause fever.. As the tooth is in smile lime I would suggest you to consult an Endodontist and get evaluated and he can also advise you to get an IOPAR [ X RAY ] done to rule out the exact condition of tooth and if it can be saved root canal treatment can be done followed by capping of tooth.. If it cannot be saved extraction followed by Immediate loading Implant can be placed.. As you have dry mouth getting evaluated for the exact cause of it and treatment can relieve as well as there is no such condition that a person wit gag reflex cannot get dental treatment done and there are certain modified ways by which treatment can be done.. As of now you can take antibiotics like Augmentin and anti-inflammatory painkillers like Ibuprofen for relief.. For dry mouth you can chew sugarfree chewing gums as well as use artificial salivary agents containing Methyl cellulose for relieving dry mouth. Drink plenty of water.. Hope this information helps.. Thanks and regards. Dr.Honey Nandwani Arora.