I am looking at a lovely scar on my left shin from box jumps, acquired back in Jan. It was max height box jump day. I missed my first attempt at 32" and ate shit on the corner. Second attempt resulted in the same. Trust me when I say knee socks offer zero protection. I've thought about shin guards myself, I would be interested to hear how they work for you.
As for the fear, I definitely had a mental block against box jumps following that. I cherry-picked WODs and skipped any with box jumps for a solid couple months after. Finally came back around, and can do 20" jumps well enough, although if I stare at the box too long between jumps it gets harder, my mind starts wandering back to getting hurt again. Had a WOD recently where women were told to do 24" RX, frankly I ignored it and did 20". I say do what you need to do to get back on the box, but don't let anyone bully/force/coerce you into doing jumps before you are ready. Try a lower box, or doing step ups until you are comfortable. If your fear is that great, try a stack of bumper plates. The edges are at least rounded, and a stack of plates looks far different from a box, that might help you get over the mental hurdle.