Ashton defeated O'Hara 24-7 but alleged the Belfast man bit his shoulder in the third round.
But O'Hara said: "I would never even think about biting an opponent - no way did I bite him and I want him to take that back.
"If I had bitten him he would have known about it - I would have taken his shoulder off!
"I have a bit of stubble, maybe that's what he thought was a bite.
Miserable NI start
"I don't know but it reflects badly on me and that's not fair.
"I'm disappointed that I lost - he had a very awkward style - but I'll bounce back."
Ashton showed off a tuppence-sized abrasion on his left shoulder after his win and the Welsh team said they would file an official complaint.
O'Hara's defeat contributed to a miserable day in the ring for Northern Ireland as their other hopefuls Cathal McMonagle, Liam Cunningham and Shane Curran all lost.