When you say you have CS4, I assume you mean Photoshop. I'm not that familiar with Lightroom.
Bring the image in at an exposure that has the least blowouts. Create and adjustment layer. Add a mask. Mask off the blenny using the brush. Before you do any adjustments, make a copy of this adjustment layer. Click on the mask. Hit control-I or command-I on the Mac. Now the layer mask is inverted.
You now have two adjustment layers. One will adjust the blenny and the other will adjust everything that is not the blenny (negative space). You have a dark subject with a lighter negative space. The eye is drawn to; high contrast, lighter and sharper areas. On the negative space layer, reduce the exposure, add some Gaussian blur, and reduce saturation slightly. For the blenny layer, do whatever make the blenny look better, e.g. bump the levels, add some contrast with curves, bump vibrance, etc.
The objective is to draw the eye to the blenny, but still have a pleasing background. An over-exposed, crunchy sharp background isn't all that pleasing. So de-emphasize the background without impacting the subject.
Disclaimer: There are always multiple ways to achieve the same results in Photoshop. I may actually know more than one way myself. I will always concede that another way may be "better".