Just got rear ended

[Porsche9]

On my way home from work in stop and go traffic I had to slow down fairly quickly to about 15 mph but nothing extreme. I look in my rearview mirror and I see a Dodge Stratus barreling towards me with tires smoking (thinking what the hell is wrong with his ABS). With no out because there were cars all around I braced myself and sure enough he hit me what felt like pretty hard. Thankfully I was not hurt. We pulled to the side of the highway and I got out and expected carnage and all that I could see were some marks on the bumperettes. Fortunately the other driver was fine and I told him to get his brakes checked because the ABS should work and not allow the car to lock the brakes.

I have an appointment with an insurance adjuster and with a hit like this that appears on the surface to have little damage is there something I should be looking for in damage beneath the bumper cover?

Thanks in advance for any insight.