Urgently need help what kinda cream is effective for scarring of mosquito bites?

My LO have this too. But it looks like the darkness isn’t on the outer layer but on the inner. It has been close to a month already and it hasn’t faded yet. I believe there was a reaction to the bite hence it doesn’t go away like normal insect bites. As an adult, I had this too and the darkness only disappears after almost 5 months. This is not an exaggeration. 😢