Herpes Simplex can be treated by an antiviral medication, but it cannot be cured. However, the sores will often go away on their own without treatment.
There is no real prevention of herpes simplex other than avoiding skin-to-skin contact with someone who has it. Using a condom during sex can reduce the likelihood of herpes simplex being transmitted to the other person, but it does not eliminate it. Washing hands after treating sores is also a prevention method.
American Academy of Dermatology