Espargaro's comments come after he struggled to ride his bike for three consecutive laps during Friday's two practice sessions due to his thumb injury.
The 25-year-old had surgery to repair a ligament in his right thumb following a massive crash during a free practice session prior to the previous MotoGP event in Le Mans.
While Espargaro admitted that the pain was too much to bear at times, he pointed out that he will give it his all during the race on Sunday.
"The pain was more than I expect because after two or three laps," he told reporters. "After the first two it was good but after three laps the pain is unbelievable in the brakes and I cannot continue. Every time after three laps I stop and I never do more than three laps in a row. So tomorrow we have to take something for the race because it's twenty more.
Espargaro even joked that he would need a full box of painkillers to complete all 23 laps at Mugello.
"For sure I will start and then I will see. We talk with Xavi Mir," he said. "He told me that one ligament is not like a bone. It needs a lot of time. Just eight days after the surgery the handlebar is pushing on the surgery (scar) all the time and because of this I'm not able to ride.
"I'm really happy and tomorrow and race day I will try to take one box full of painkillers and I will try to race!"
Despite experiencing intense pain during both practice sessions, Espargaro was extremely surprised to have finished seventh.
Offering an explanation as to how that was the case, the Suzuki rider said: "Maybe this pain is higher than the hand. We are trying our best. Even with the speed on the worst track on the calendar the difference is six tenths. We have to be proud. I think soon we will have good things to try and to improve. We just need break."