Ct scan results good or not???

[HopeFaith]

Hello everyone,
I need some help my mother received her CT results today. I don't know rather it is good or not please help. She is ER/PR+ Her2+ mets lungs 3 nodules, arm lymph nodes and skin. Here is my question shrinkage or stable in all areas expect 1 lung nodule it actually has doubled from 6mm to 13mm and Skin is completely clear with no new findings. She is on TDM1 this is after 2 doses. But it took the CTC 3 1/2 weeks to start her treatment after the 1st CT so we don't know if the growth was before treatment during the long wait or since treatment. Dr. thinks before treatment and that is not likely all other areas are showing improvement but this one. He wants to continue treatment and rescan after treatment 6 with would be about 2 1/2 months. Is that 2 long to wait or normal