My upper lash line is really sensitive – for whatever reason, either the movement of a pencil/brush on the area or the product itself, but either way, it causes my my lash line to swell up and get a bit red and swollen. I do it from time to time, but it usually means the look is purely for blogging purposes and I remove as soon as I’ve taken photos to avoid too much swelling (it usually lasts 4-12 hours).