Infection is the most common cause of such fevers, but I would strongly suggest that you visit a doctor and get the child examined to rule out conditions like intestinal obstruction which could also give rise to such conditions. The paleness and cold to touch could indicate a condition called shock which occurs due to low amount of circulating body fluids, a condition that could occur in case of certain bacterial infections which might need to be treated urgently. Continue sponging the baby as you are doing and also give ibuprofen or alternatively Meftal syrup (mefenamic acid) which is more effective in reducing temperature but once again, let me emphasize the significance of visiting a doctor.