My freinds mom saw me naked in the bathroom.?

okay... i went to my freinds house last night after i was done studying for midterms :/.... to make a long story short... i ended up sleeping ove his house...i took a shower that night at his house cuz i started getting itchy... about a minute or two wen get out of the shower i hear his moms footsteps coming into the guest rroom... i thought the lock was locked on the bathroom so i thought nothing of it.... she comes into the bathroom not noticing me at first...when i finally said im naked she turned around a stared for at least 5 seconds then she says " im sorry" and leaves... now im embarrased bc my friends mom saw me naked... what should i do??