Well your Duncan LPS ended up in the SPS section that ain't good for the Duncan either
Yes you can dip your coral but having it in your tank already dipping is to late.
If it had pest they would be already wandering your tank which other coral they can bother.
Many ppl use Bayer as a dip as it will kill almost every reef pest alive but not the eggs on the coral, eggs can be removed manually or keeping it in a QT for 6 to 8 weeks and dipping it on a weekly schedule, if we talking AEFW every five days of course.
So dipping in Bayer goes like this, you go to a Lowes or HD and look for this,
Poor a little in a cup where you coral can fit in and mix it to a light milky color with saltwater from your tank.
Let it sit 10 to 15 min a swooshing it around so now and then.
Remove it from the dip and in a separate cup with saltwater rinse it good, than move it to another cup with saltwater and rinse it again good, reason why is that you can't rinse it enough to remove any Bayer on the coral but two rinses should be enough.
After that inspect it good and if save place it back into the tank.
Disregard all dipping water and rinsing water, I poor it along my foundation of the house as it will help with termites.
Looking at your coral it looks like a fresh cut and glue did some damage to the stem of your Duncan.