Hi everyone, I am a new mommy to my baby girl Isabelle

I recently took her to the vet (Friday) and now she has a lump in the area she received the shot. Is this normal?? She isnt acting sick or strange at all.
Also she doubled her size in one month!! She went from 2 lbs (12 weeks) to 4.8 She has a thinner frame and is still small, but is that normal? she was expected to be 5lbs full grown. Guess thats not happening. She is 16 weeks now.
Appreciate the help!