Do you think i should be worried about my foot sweating in my ankle cast?

Nothing much you can: Do about it, except keep it clean and may use a fan to dry the toes, etc. Better still move to iowa, as we have plenty of snow/ice and I am sure all iowan wouldn't mind sharing it with you, and even your whole clan. Do check with your surgeon about it. I generally get casts changed, if its wet completely or skin is macerated or if its smelly. Good luck, and consider iowa for the cold.

Sweat: As stated there really isn't much you can do about it. If you have concerns of any kind , see your treating physician.