Hi.. Welcome to HEALTHCARE MAGIC.. I have gone through your query and can understand your concern.. As per your complain you are having an outbreak of HERPES SIMPLEX VIRUS 1 INFECTION and it is the cause for the cold like symptoms and cold sores are erupting in mouth.. Although cold like symptoms are not seen in all cases but at times the cold like symptoms occur first followed by blister formation.. You need to consult a physician and get evaluated as Herpes can be confirmed by clinical examination as well as investigations like Viral Culture, blood tests and at times even Biopsy.. For Herpes you need to take Oral therapy with antiviral drugs like Acyclovir, Valacyclovir, Famicyclovir etc.. Coat the blisters well will antiviral ointment containing Acyclovir.. For pain and if you also have fever Tylenol can be taken.. As it is a contagious infection avoid close contact with anyone and do not share your personal belongings like towels, glasses etc.. Maintain a good Oral hygiene and do not worry as the sores will resolve in approximately 2 weeks or even less.. Hope this information helps.. If you find the answer helpful please give me a Five Star Review and click on found the answer helpful as a token of appreciation.. Thanks and regards.. Dr.Honey Nandwani Arora..