Hair is something I give a fuck about. Their hair, all of them except maybe Bonnie's which just needs a good brushing and a better conditioner, hurts me on a spiritual level.
The bleach used here was probably too strong. The hair is showing signs of damage with how lanky it looks, and given the color that Penny's hair was to begin with he didn't need too much in order to get a vibrant color to take. That pink is surprisingly not bad, likely Manic Panic or Arctic Fox but I'm not sure which. It'll fade quickly if he isn't using a color depositing shampoo/conditioner/
clenditioner (I included a link because if any of you dye your hair even normal colors regularly this shit is great.)
Also the fact that Kevin is doing Penny's hair given what his looks like is amazing and hilarious.