So decided to timeskip to the next day where Little Mac is going to ask Bimbette about his burn scar

The next day Little Mac returned to Forest to see Bimbette again. Once again the Mutant Doe was happy to see him but she seemed a little worried he was going to ask her more questions about her past.

"Hi…" Little Mac said as he stepped in "...Um...There's someone who would like to meet you but before I take you to him I just have a favor to ask you."
"A...Favor?" Bimbette asked not sure what he was going to ask

"Yeah…" Little Mac said "...Now that I know what you are...But I already knew you can heal stuff...I just wanted to ask you...If you could...Well...Let me show you…"
He turned around and took off his black tank top that he wore in every boxing match...Bimbette gasped as she saw the enormous burn scar that covered most of his back!
"Little Mac!" She exclaimed "How...When did this happen?"
"Shortly after you had to leave New York…" Little Mac sighed "...Some of the kids in the orphanage wanted to bake a cake...I think it was somebody's birthday or something...And the adults had mostly left us unsupervised...I didn't want any part in it...I was just sitting at the table reading...But when disaster struck...The flames...Jumped onto my jacket...And I remembered too late stop drop and roll...By then I got burned pretty bad...Can you heal it?"
Bimbette winced...She already had a pretty good idea of why it wouldn't work...But she would at least try!

First she laid her dainty three fingered hands on the scarred parts of Mac's back and concentrated hard...Mac trembled at the touch but he also felt a comforting warmth from her hands…

However nothing changed...So Bimbette decided to bring out the big guns...She licked at the scar with her healing saliva...But that did nothing either…

So she decided to tell Mac the truth.

"It's not working…" She said "...You know when you get a blood stain on your clothes and if you don't treat it quickly the stain will set in?"
"Yeah?" Mac said

"Well...It's like that...Your body has already healed itself but the 'stain' has set in...There is nothing I can do now...I'm sorry…"
Little Mac sighed but he wasn't angry, Bimbette's explanation did make sense to him...So he put his shirt back on

"Oh well…" He said "...It was worth a shot...Can you come with me? I want you to meet Glass Joe."
So really works out that I established Little Mac has a scar he's sensitive about and his love interest is a Mutant with healing powers and here I show the limits of such abilities