Baby chipped tooth now looks slightly green

[Floyd2020]

Hi, my 18 month old badly chipped her front tooth around 4 weeks ago. Dentist at the time checked it over and said to keep an eye on it discolouring.
We’ve notice this morning at the back it now looks green! Trying to get an appointment but dentists aren’t open till tomorrow. Is this the tooth infected? Is she likely to lose the tooth?
Thanks in advance from a very panicked parent

 

[Floyd2020]

 

[Floyd2020]

Apologies for the poor photo quality, she’s pretty wriggly