If the mouth ulcer is almost healed but the submandibular lymph nodes are still swollen and painful, if there is only a mouth ulcer, it can be treated with medication such as Rejuvenate Liquid, and if there is a disease such as mumps, it should be treated with antibacterial therapy accordingly. If there is no other disease that can cause submandibular lymph node swelling and pain other than mouth ulcer, then the submandibular lymph node can return to normal after the mouth ulcer heals completely. Rehabilitation solution, chlorhexidine gargle, and compound borax solution can be used to promote the healing of mouth ulcers. If other infectious diseases such as acute suppurative parotitis exist at the same time, antibacterial treatment such as cefazolin and amoxicillin is needed, and when pus is formed, incision and drainage should be made in time in order to cure acute suppurative parotitis or other oral inflammation, so as to make submandibular lymph nodes return to normal. All of the above drugs should be used under the guidance of a doctor, there are other diseases that may cause submandibular lymph node swelling and pain, it is recommended to go to the hospital, to clarify the cause of the disease for targeted treatment.