It sounds like your husband probably has a virus of some sort. Usually the worst of the symptoms last a few days, but he could feel pretty awful for a week or more.
You really need to watch for signs of dehydration and serious illness. If he isn't able to drink or keep down fluids, or if it seems like he is really burning up (it might be in your best interest to go buy a thermometer - they cost under $10) or has a temperature of 103 degrees, you should take him to the ER. Also, if he starts to experience severe pain in his stomach area (particularly in the lower right side), you need to take him to the ER.
Continue to give him pain relievers every 4-6 hours as needed, and try to encourage him to drink as many fluids as possible.
If you have any other questions, please feel free to ask!
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