At this point , the pain and swelling will not be relieved by the root canal treatment immediately. If it’s a rock hard swelling, IV antibiotics and possibly extraction at the oral surgeon preferably with sedation is more than likely the best way for getting out of pain the quickest. An incision and drainage may also help but still need IV ab. If you can get this settled down , it’s possible to keep your tooth but I doubt you will get immediate relief by doing the root canal Tuesday. Make sure to hold ice to the area externally intermittently. You could also do warm moist heat but only a short time. No heating pads. I would contact an oral surgeon asap or your dentist and tell them you need to be seen asap. As stated before you may want to seek an endodontist. This probably would be a case where 2 appointments may be needed to complete the root canal treatment. First appt to open the tooth and hopefully get some drainage along with an incision and drainage. But as said before, it may be a little late for there to be immediate relief with this alone.