She might have spread some type of sore to you, but don't worry they are usually harmless. If u've ever had the chicken pox (a variation of the herpes virus), it's linked to causing cold sores (another type of herpes), don't confuse this herpes with the other more serious one.

Another more simple explanation, is maybe you have a food/drink allergy?

They go away on their own after a few days.

Thanks for the info :)

however, the spots are still there after 1 month. There's no pain or sores, but i'm just concerned why they are still there... Any idea?

Hmm, that is quite a while to be having those spots. Have they decreased or increased in size? If so, have you been ill or under a lot of stress? Also, do you keep touching them, say with ur tongue or ur fingers? Stress or touching a wound constantly can delay the healing. I would recommend asking your doctor, at least for peace of mind.