A man from New York is preparing to undergo a complex operation to save his life after a pain in his jaw led to the diagnosis of a deadly form of cancer.

When Gregory Powell noticed the aching on the left side of his jaw had worsened over the course of two months, the 31-year-old visited an ENT specialist in mid-June expecting to be prescribed some simple medication to quell the pain.

“It was kind of like a toothache,” Powell, a freelance production designer from Crown Heights, Brooklyn, tells PEOPLE. “There would be a tenseness in my jaw and it would hurt to open my mouth. If I talked a lot, it hurt. It just got worse in the last two months, and it would come and go, but it soon got really painful and I couldn’t sleep.”

But the doctor quickly concluded that the problem was more serious than Powell could have imagined.

“He felt the mass in my face, he was just kind of poking at it and I was wincing in pain,” Powell recalls. “He just stopped and he looked at me directly in the eyes and he’s like, ‘I have really bad news for you.’ “

Within minutes, Powell was undergoing a biopsy on a tumor the doctor observed in the space under his left earlobe and cheek, right on his jawbone.

“I was like screaming,” he recalls, “just because it’s so painful and discomforting.”

In a few days time, Powell learned he was diagnosed with Stage IV Adenoid Cystic Carcinoma, an aggressive cancer that begins in glandular tissues, most commonly those found in the oral cavity. While tumors may not cause pain in their early stages, advanced tumors can become painful, the National Institutes of Health reports.

There is no effective chemotherapy to treat the tumors, and, when possible, patients typically have surgery to remove the tumor, followed by postoperative radiation therapy. Patients can also experience paralysis if the tumor progresses and spreads to the nerves, and because of this, doctors told Powell they would have to remove part of his facial nerve and replace it with one from his leg.

The news was heartbreaking to hear, as Powell had hoped the treatment would have been far more simple.

“I thought they were going to cut it out of me and I would walk off into the sunset,” he says. “I thought it was all going to be fine.”

Yet, even with surgery, ACC tumors are persistent and often recur and progress after five years, according to the Oral Cancer Foundation.

Powell’s operation, set tentatively for August 20, will require the removal of a large portion of his jaw, and may leave his appearance drastically altered for the rest of his life.

“They’re going to cut me open, cut out the tumor, cut out my jaw bone,” he explains. “They’re going to put a prosthetic in for my jaw to replace the portion they have to remove, and then they’re going to put me all back together.”

After a two-week stay in the hospital, Powell will undergo radiation therapy for six weeks, which doctors tell him may take away his ability to taste, alter his ability to smell and leave painful sores in his mouth.

Then comes the waiting game: a year after the operation, doctors will assess how much of Powell’s facial nerve has regenerated, and from there, he will enter physical therapy to relearn how to move his face, rediscovering every day things like winking, smiling and blinking.

“I just feel numb,” Powell says of how quickly things have progressed since his appointment with the ENT specialist just weeks ago. “I talk to someone or explain what’s going on to a friend, and it’ll hit me a few hours later, and it’s like, we’re talking about me. It’s like actually happening to me.”

Because he doesn’t have health care, friends of Powell started a GoFundMe page to help pay for his medical bills — which he expects may exceed $1 million when all is said and done.

As he prepares for the upcoming surgery, Powell says he’s still trying to find humor through the ordeal and even told friends he’d like to wear a “cool eye patch” while he’s in the hospital to cover his left eye, since he won’t be able to blink.

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“I might as well have fun looking like a pirate!” he says. “But I’ll practically need it anyway.”

Once he makes it through his recovery, Powell hopes to raise awareness and funds for research into the ACC — something he had never once heard about before his diagnosis.

“I would love to help people in any way I can, after I make it through this,” he says, before adding that other ACC survivors have reached out to him over social media. “I want to help other people like this. It gives me some hope.”