/diy/ - Do It Yourself

I could use some first-aid advice.

Backstory:
I use icepacks on a fairly regular basis for sciatica pain.
I think the pre-made kind are kind of pricey for what they are, so I made one using internet instructions using a 2:1 mixture of tap water to 99% isopropyl alcohol, double-sealed into quart-sized ziplock bags.
Today when I got home from my bike ride, I pulled a commercially-available icepack, and the home-made icepack out of the freezer, applied the one to my lower back, and the home-made one to the back of my left thigh. ~15 minutes passes, and I take them off. The skin where the home-made one was had frozen nearly solid and was almost dead white with pretty much no feeling at all in it!

After about half an hour it warmed back up, and the affected area is what is in the picture. I have feeling in it, it's not blistering, it's just pink. This is a degree of frostbite, apparently minor, but having NO experience dealing with frostbite, I'm concerned.

Based on what I've said above and the pic (sorry for the poor quality), is this anything I should be seeking medical attention for? I'm thinking probably not, that it'll be uncomfortable for a few days, but then it'll be fine.

Authoritative comments from people who have experience with this greatly appreciated.