If you know your vet well he may sell you the lidocaine.....or...if you use a place such as Valley Vet supply, your vet can call in the RX to a 800 listed on their website, or he can write you a RX for it, and you can send it in thru the mail.
As for goin in to the Feedstore....no they don't have it since it has to have a Vet RX.