26 & Carboxytherapy left me with lumps on my chest & arms? (Photo)

I had over 30 weekly sessions of carboxytheraphy to treat stretch marks on my breasts, thighs, arms and tummy. I had 15 treatments before lumps developed on my chest and arms. The doctor said they would disappear and carried on the treatments. My last treatment was in April 2022 and as you can see they haven’t disappeared.  The lumps have now hardened and are still visible on my chest and arms.  Why do you think this has happened? How could I resolve this? I am 26. Thank you so much.