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
Thank you svickstc for providing this link. There are so many different sites with only part of the downloads needed to sbf the droid 3, its nice to have them all in one place, as well as have a user be able to attest to its legitimacy/functionality. Thank you!