I dropped a cinder block on the top of my bare foot?!

I dropped a cinder block on the top of my bare foot?

I did not get an open wound but there is a weird dark purple area - like a blood blister where it hit. I ran my foot in cold water with epsom salt and soaked it. Then I wrapped a cold compress and am elevating it. It still is throbbing like it just happened - been about 30min. Should I see a dr. today or can I wait?

Most likely from what you're saying you have a rather large bruise on your foot (of course if I could see it, I'd be able to tell more).

You are in fact administering the correct first-aid for an injury of such at the time. Keep it elevated for at least 30 minutes and keep the cold compress applied for 15 minutes, remove it then re-apply the cold compress (you can do this up to one hour or two - however, do not exceed 2 hours). I would also suggest that you take some sort of pain reliever such as Tylenol, Motrin or some sort of Ibuprofen!

If the pain persists after about 12 hours, I would suggest you schedule an appointment with your FNP or MD (doctor). You may have some how broken a tenant in your foot (or even a toe) or damaged blood vessels some way due to the heavy impact from the cinder block.