Thanks for your question. I'm not a doctor, but I do have herpes and have done some research on this issue.
Yes, you can donate blood if you have the herpes virus as long as you are feeling well and without lesions at the time. Herpes actually lives in the mucous lining of the mouth and genitals, not in the blood. The blood only carries antibodies of the virus; herpes is not a blood-born virus. You can check the Red Cross Blood Donation Eligibility Guidelines for more information about donating blood.