Mark Hoppus stressed the importance of paying attention to changes in one's body and getting them checked out by sharing a text conversation he had before his cancer diagnosis.
Hoppus, who was diagnosed with diffuse large B-cell lymphoma, is currently undergoing chemotherapy to treat the illness.
Taking to his Instagram story for the viral "How It Started vs. How It's Going" challenge, the Blink-182 bassist shared how his cancer battle started by posting a screenshot of a text conversation he had with a contact named Jill, presumably his doctor, on April 20.
MORE: Blink-182's Mark Hoppus reveals cancer diagnosis: 'I’m trying to remain hopeful and positive'The text reads, "Hi Jill. For the past couple of days I've had this dull sore lump in my shoulder kind of right where it connects to my neck that could either be fatal lymphoma or a sore muscle."
Hoppus, 49, also asked, "At what point should I be concerned and have it looked at?"
His doctor encouraged him to set up an appointment for that afternoon.
In the next story, Hoppus showed "How it's going" with a photo of himself flashing a peace sign while undergoing chemotherapy.
MORE: Blink-182's Mark Hoppus reveals his mother beat the same cancer he's fightingThe subsequent story linked to a post from former band mate Tom DeLonge, who announced that Hoppus is "is almost done with his treatment" and in the "last stretch."
Late July, Hoppus assured fans that his cancer treatment is working and proved it by hopping on the live-streaming site Twitch to play the bass, something he said he hadn't been able to do since he was diagnosed.
"I still have months of treatment ahead but it's the best possible news," he said at the time.