It was your face mom...says Eli

Eli (my 7 year old) and I have this ongoing struggle over lying. I don't know when it started but it rears its ugly head about once or twice a month. It goes something like this every time...
Example from tonight taking a shower...
Me: Eli, did you wash everything?
Eli: Yes
Me: Did you wash your (and I start naming everything until I get to armpits)
Eli: Yes (then he looks funny)
Me: Did you really wash your armpits?
Eli: Yes - (but now he's making that guilty face again that he does every time we get sucked into the is "is he lying" fight.
But then he says "no" - so I say "well wash your armpits" but then I think as any good mother would who realizes she needs to spend the extra energy she does not have at 8pm while bathing her children to make a teachable point..."Eli, you just lied to me didn't you?"
Let me point out that I admit I am a little sensitive about lying b/c I struggled with this as a child! I did it often growing up - usually at a younger age I ended up confessing to my mother but as I got older I really struggled with those little lies that don't hurt anyone but keep you from getting into heaps of trouble. So, I don't want Eli to fall into that trap.
Back to the bathroom...
As the story usually plays out....I realize he lied, tell him he will get a punishment for it, then he starts crying hysterically and changes his story yelling "You don't ever believe me..I'm not lying - why don't you believe me?" Then I go crazy in my head b/c 'didn't he just admit he was lying?' So, am I hearing things - is he confused - am I confused - God help us we are all confused now!
BUT THIS IS THE BEST PART....this time he looks at me and says "IT WAS YOUR FACE!" (I think meaning my face (or the look I was giving him) made him start cracking up so he looked guilty) but the thing is he just kept saying "IT WAS YOUR FACE THAT MADE ME DO IT - YOUR FACE!" Then Ian gets out of the shower and looks at me and says "Mom...I think you are beautiful!" Oh, the life of a mother - no, I didn't end up punishing Eli b/c he was so hysterical after the shower and we were both so confused as to if he really had washed his armpits that I was too exhausted to even think about it again! Lesson lost? At least I know that my face now has power to make others do things they regret! oh my...