How can i know the difference between fordyce spots and herpes?

Here are some ...: Fordyce spots are ectopic, not-hair-follicle-related sebaceous glands, appears as 1-3-mm papules, and are painless. But herpes are virus-caused skin infection with prodromal skin hypersensitivity followed with a cluster of blisters on an erythematous patch of skin, commonly on foreskin / glans penis, but maybe elsewhere. So, history and physical findings can easily differentiate them.