Ok, some moron almost sideswiped me on the highway tonight. (I have a 91 civic hatch)

As a result, I panicked and when I was trying to slow down to avoid getting hit by said moron, accidentally downshifted from 5th to 2nd gear-while going 45-50 mph! I meant to go into 4th and immediately went back to 4th once I realized my error as the car revved WAY up in 2nd.

I just did this once, will my engine be screwed or what damage could this have caused? Thanks in advance for any info anyone can give me.