The top U.S. gymnast missed out on presenting with her Final Five teammates at the MTV Video Music Awards in New York on Sunday (28Aug16), after she was briefly hospitalised for a mystery ailment.

She returned to seek doctors' care later that night, when her publicist told she required treatment for a "seriously infected past mouth injury".

She returned to social media on Tuesday (30Aug16) to share an update with fans, revealing she is now on the mend.

"Hey guys! Just wanted to let you know that I'm doing ok!," the 20-year-old wrote on Twitter. "I had a complication from a prior injury that caused a cyst to grow on a bone in my mouth.

"Got it removed and feeling much better now! Thanks for all your concerns and prayers and HUGE thank you to the doctors that have taken care of me these last four days!"