Is the house already sold? If so, then don't worry about it, it didn't affect your sale.
However, if you are still in escrow, then it's a different story....Did the appraisal come in lower than the buyer's purchase price?
If the appraisal came in at the purchase price or above, don't waste your time trying to get it re-appraised. The bank just wants to make sure they are not loaning money on a home that's valued below the purchase price. Most of the time (In my experience) appraisers come in at the purchase price, even if the property could easily appraise for 10k more.
If you really think the appraisal will affect the sale of your home, then ask your agent for a second evaluation.