A medical expert believes Mike Tyson is ‘at risk’ of more stomach ulcers ahead of his controversial boxing fight with Jake Paul next month. The 58-year-old is currently preparing for his epic comeback, four years on from his exhibition bout with Roy Jones Jr. There are, however, many who fear for Tyson as he prepares to come out of retirement to face Paul. Earlier this year, the boxing icon was forced to postpone the showdown after suffering from a stomach ulcer. Paul then fought Mike Perry on July 20 instead, with the 27-year-old winning via knockout. Tyson insists he’s feeling good as he pre…