How dangerous is formalin (4%) really?

I've been working for almost 2 months now at a pathology lab as lab tech, and while pumping up a lobe of lung the tube we use to inject it with formalin shot loose from the formalin tap. My arms were covered in formalin, and I washed it off as quickly as I could. Nothing hit my face, and I was wearing safety goggles.

Since formaldehyde is a known carcinogen, I was wondering how dangerous a 4% solution is compared to stronger formaldehyde solutions. What kind of damage can a 4% solution cause if left on the skin? I've heard some stories of coworkers about others who had tiny spatters of the stuff in their eyes, but all they told me was that it hurts like hell. I haven't heard any stories of permanent damage (yet).