It depends on skin sensitivity and how big a zap you get. Mature hairs take more juice than fresh ones.
When I am finished an electrolysis appointment, my cheeks look like I have a bad case of acne. My upper lip looks like someone whacked me there. My neck and chin look like I have a rash. The redness is gone by the next day, and the swelling goes down after a day or two.
I am retired so I don't have to worry about work, but I do sometimes have fire department practise on the evenings of my electrolysis days. I just explained that I wouldn't look my best sometimes, when I first came out to them.