Right, acid test :
Reboot the prime, hold the POWER and VOLUME DOWN buttons whilst it's powering up, wait for the text to appear, do not touch anything at this point. Take a careful note of what it says. If it says "unrecoverable bootloader error", you're boned. That's a hard brick.
Your only option is to contact ASUS and speak to them and see if there's anything they can do to assist you. Since you were messing about with the recovery image the best you can hope for is either some divine luck and they accept an RMA for it, or be prepared to fork some money to get them to mend it.
If however after about 15 sec or so it throws up three icons, then you may yet be able to save the prime, hit volume down ONCE and then volume up ONCE and it should state that it's trying to bring up the fastboot protocol. From there you've got a fighting chance provided you do not under any circumstances attempt to flash a stock ASUS blob.
If you can bring up fastboot via this method, then a quick search for the CWM or Team Win guides for ADB/Fastboot installation will get you back into recovery and from there you can set about unbuggering your tablet.
If you attempted to flash a custom recovery onto a -locked- prime, then you may have more serious problems than that. Then you're looking at hard brick territory again.
Hope this helps.