Hi. Thanks for the query.. As per your complain cold sores caused by Herpes simplex virus are seen most commonly around the lips although the lesions can also be seen over cheeks,nose and in severe cases can be seen in and around the eyes.. The viral infection can also infiltrate the nerve supplying the face like facial nerve or Trigeminal nerve and can lead to pain on face over the affected side.. The swollen gland under the jaw can also be due to viral infection causing infection and inflammation of the lymph nodes and causing swelling in lymph nodes.. The other cause can be infection in the submandibular salivary gland or clogged duct of the gland with foreign body or crystalline stones formed by the minerals present in saliva and can lead to selling and pain and it can be unrelated to the facial lesion and it can be due to some other conditions which can cause crusty lesions like Actinic Keratosis.. You should consult an Oral Physician and get evaluated and get treated according to the diagnosis.. You may also need consultation with a Dermatologist for treatment with the skin lesion and get treated accordingly.. As of now you can take painkiller like Ibuprofen for pain relief.. Hope this information helps.. Thanks and regards..