First things first is you should read your purchase contract. If you are using a Buyers Agent, you're likely using the standard forms, and your agent should be able to explain your contingencies and when they expire. If you are not using a Realtor, then you should consult an attorney.
If you are using standard Virginia Contract with a Home Inspection Contingency then there are options for you to withdraw your offer within the guidelines outlined in the contract. If you are working with an agent you can discuss your options with them. If you need other advice and you are not represented by a buyers agent then you will need to discuss your options with a real estate attorney.
Look at your contract and ask your agent. The standard contract in Northern Virginia gives buyers the option of voiding the contract if they are not satisfied with the home inspection. Your agent should be able to advise you on this matter.
Exactly what Frank said. You can't back out for that specific reason, but you can potentially back out for other reasons/contingencies. Speak with your agent/broker and/or a real estate lawyer for further guidance.