Welcome to NeuroTalk:

Sorry you are having this reaction.

Have you tried another brand of insulin? There are many new
types now, and each may have a different allergic profile.

Are you type I or type II?

Do you get reactions from other injections? bug bites?
Swelling in hands, feet, stomach with no warning?
Do you take an ACE inhibitor like lisinopril, vasotec etc?

These questions are for people who may have angioedema.
This is a separate thing and causes vasodilation independently of the drug you may be injecting.

Diabetics can get very low in magnesium...they lose it in the urine. If you don't eat specific foods to provide for this loss, then
muscle stiffness and foot pain may occur. If it gets low enough it will affect the heart.

Try soaking in an epsom salt bath (8oz to a bath tub of warm water)...and see if this helps. If you notice some improvement you need to start eating more magnesium rich foods, and or take a supplement. There is even a Morton's Epsom lotion now, available to help ...Amazon and WalMart carries it.