It's been 4 wks since a herpes blister appeared on my upper lip. the blister is gone but redness remains. how contagious is my outbreak still?

Oral herpes: Hi, if the blister is completely crusted then there is no risk of being contagious anymore.

Should be okay: The virus is at it's most contagious while you have the blister, about 7-10 days. The redness may be some scarring and it should not be contagious.

Still contagious: Even without the blisters, the herpes virus can always be contagious, although it is most contagious immediately before an active outbreak of blisters.