sounds like a boot loop, you need to SBF the phone basically APFast boot back to stock rom wit the SBF Files.
You Need to download:
RSD Lite (Found in link i provided)
Droid 3 SBF File (Found in link i provided) Use the OTA # 1
Follow the instructions in the link
(
[SBF] Droid 3 Fastboot files (5.5.959 and 5.6.890) - RootzWiki)
do a little more reading and follow the instructions next time
UNLESS you made a nandroid backup, in that case boot into recovery and restore from your backup!! AND if not next time remember to make a backup