Ackman had teamed-up with Valeant to help the health care company try to buy the Botox maker. Their hostile pursuit, announced in April, was thwarted by Actavis, which agreed in November to buy Allergan in a $66 billion deal.
Pyott described the months following the Valeant offer and before the Actavis deal as "all-consuming."
The Allergan chief said on "Squawk Box" he had divided the management team—appointing President Doug Ingram and Chief Science Officer Scott Whitcup to run the day-to-day operations. "I will concentrate on the raiders, investors, public relations, all the above," he said.
"Between the day the Valeant offer was announced, April 22 and ... pretty much today, the value of the stock has increased about $20 billion. Part of that isn't a takeover premium at the end, but we constantly ramped up our performance," Pyott said.
Ackman's bet on Allergan netted about $2.2 billion—a big winner for his Pershing Square Capital Management whose main fund returned 40 percent last year, nearly four times the gain of the in 2014.