An Ottawa-area boy who suffers from a rare and painful blistering skin disease is recovering in a Minneapolis hospital, after undergoing a second potentially life-changing transplant.

Jonathan Pitre, known as the "Butterfly Boy" because of his delicate, blistering skin, received a second transfusion of his mother Tina Boileau’s stem cells in April.

In a Facebook post Tuesday, Boileau said the donor study tests are showing that her son is officially growing her cells.

Pitre was born with a severe form of epidermolysis bullosa (EB), an incurable genetic collagen disorder. The condition causes a never-ending series of raw and painful blisters -- some of which he’s had for years.

His mother told CTV News on Wednesday that the positive turn in Pitre’s long and painful treatment was “exactly what we needed.”

Boileau said her son has had “infections on top of infections” and endured much pain over the past year. The second stem cell transplant has been really hard on his body, she said, but there now seems to be light at the end of the tunnel.

“Yesterday was just the greatest day. We were speechless. Jonathan hugged me and we were like, ‘We did it,’” she said in an interview from the hospital.

Boileau said that even some of the nurses were crying when Pitre received the good news.

“It’s finally now feeling like it’s all been worth it.”

However, she pointed out that if Pitre is unable to grow his own cells, he could be diagnosed with Graft vs. Host disease – a condition where the donor's cells take over the host's organs and bodily functions, leading to complications.

“We still have a long road ahead of us, but you know what, this is definitely what we’ve been waiting for,” Boileau said.

The $1.5-million transplant procedure Pitre is undergoing is currently only performed as a University of Minnesota clinical trial.