Bob, as stated earlier, contact your insurance company. As an Insurance Adjuster, I run into this problem frequently and most homeowner policies cover this. Normally, we would recommend replacing the drywall that got wet, replace the insulation and paint the whole ceiling. However, most of the time, these repairs aren't going to cost much more than the deductible on your policy, depending, of course, on the amount of the deductible. A lot of the new policies have a percentage deductible based on the amount of insurance you carry. If your adjuster comes out, he may find more damage than you can see. Damaged floors, carpet, etc. If you don't want to, you do not have to file a claim after you find out what the insurance company is going to pay for repairs. If the settlement is only a few dollars over the deductible and you've had other claims recently, you might want to just foot the repairs yourself and not have the claim on your record.
Either way, if you live in the Southeast, you're right to be concerned about mold. But once the drywall and insulation are removed, the mold problem is removed also. Once the joist and upper floor dry out, there won't be any mold growing. You can also spray the joist and upper floor with a mild solution of bleach, just to ease your mind.