Howe had surgery on March 18 after suffering a compound fracture to his left forearm the previous night in Collingwood's season opener against Geelong.
He spent time in hospital this week and the additional treatment is a setback that will delay his return to playing, which the Magpies hadn't put a time frame on.
"I visited Jeremy in hospital and unfortunately he's got an infection," coach Craig McRae told reporters after Collingwood's win over Richmond on Friday night.
"It's not setting back the injury itself, it's just slowing down the recovery of certain parts like being able to maybe run by now.
"But the bone itself is healing, so that's a positive.
"If you're watching, Jeremy, we miss you mate, we love you very much and we hope you can get back to the club soon."
Howe fractured his left forearm in a horror marking-contest collision with Geelong's Tyson Stengle, which sent him flying in the air before landing heavily.
The 32-year-old was in agony after the third-term collision and play was held up for several minutes until he was stretchered off the field.
The Seven Network opted not to show replays of the incident.
The setback is a blow to Howe, 32, who had played 24 games last season after only managing 12 appearances across 2020 and 2021 due to injuries.
"Our main priority is Jeremy's health and we will continue to support him as he recovers," Collingwood football boss Graham Wright said in a statement.
"The infection was picked up early by medical staff, and we don't foresee any long-term issues.
"Despite the slight setback with his recovery, in true Jeremy style, he is in good spirits."
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