Since when is this happening?
Are you on any medications / herbs / supplements?
Were any investigations done for your hand symptoms?
Any significant past medical or surgical illness?
I would look for the following conditions with red, swollen and hot hand;
1) Cellulitis; this is infection of the skin and subcutaneous tissue. This will need antibiotics as soon as possible.
2) Superficial thrombophlebitis (inflammation in veins); usually this happens after an intravenous drip in forearm or arm, but can occur spontaneously also, which can be an allergic or infective phenomenon. Again examination by a doctor as soon as possible would be required.
Please feel free for your follow up questions.