Hi... Thanks for the query.... I have gone through your query and can understand your concerns... As per your complain as you have Oral Herpes which is a viral infection and for which medication has to be taken daily for long term to prevent recurrence of infection, as you have stopped taking the medication for 2 weeks there is a possibility that in the absence or resistence for the virus to multiply there has be increase in number of viral count leading to infection and eruption of cold sores.. You can once consult your treating physician to confirm whether it is cold sore or not and blood investigation like Antigen-antibody reaction and vial culture can help in confirmation and in case of herpes you should start taking the medication again and also apply topical antiviral ointments like Acyclovir ointment.. Hope this information helps.. Thanks and regards. Dr.Honey Nandwani Arora.