Hi Iyoni,
The fact that he kept asking you for nude pictures would indicate that he may have only cared about pursuing something casual with you.
He probably hasn’t texted you in a week because you kept saying no to the nude pictures and doing a FaceTime in your underwear wasn’t enough to appease him.
If you’re looking for a serious relationship, this guy may not be the right candidate for you.
It would be best to let him go.