To put your foot in it means to say something foolish that could potentially mess something up, but in this context the speaker is warning against not saying something intelligent to make thoings better.
Context: When you are as ugly as him and romance strikes, the last thing you need is to open your mouth and make it better by saying something intelligent.
Hypothesis: When you are hideous as him and romance strikes, the last thing you need is to open your mouth and put your foot in it.

Given this context, determine if the hypothesis is true (Yes, no, or unknown)?