Nick Cannon is stoically dealing with the tragic death of his youngest child ... saying he will absolutely keep the infant's memory alive.
We got Nick leaving an endodontist's office where he had 3 root canals ... but he stopped on his way in and his way out to talk about Zen's passing. As we reported, Zen was only 5 months old when he died Sunday from brain cancer.
Nick got a tattoo of his son, and says that's only the beginning of what he plans to do to make sure Zen is in his thoughts and prayers.
Nick broke the news about Zen's death Tuesday on "The Nick Cannon Show" ... and his emotion was palpable.
He says Zen's mom, Alyssa Scott, is dealing with the tragedy as best she can, and he's doing the same. Nick and Alyssa kept Zen's health issues private during the cancer battle, so it was a real shock to hear the little boy had passed.
Nick spoke about Zen's passing several times during his show this week, thanking fans for their support and condolences.
As we reported ... Nick says the tattoo in honor of his late son Zen "... was a lot of pain, but it was well worth it. I enjoyed every moment of the experience"... adding that now he will always have his son by his side.