Rct efficicay for small sample

I have baseline and post-treatment questionnaire data on behavioural treatment and control groups. Each group has less than 10 participants.

I have missing data both on baseline and posttreatment outcomes (10% of all values are missing). The data is missing completely at random.

Do you have any recommendations on how I can analyze the efficacy between groups and by time? I am mainly stuck on how to do this given the small sample size and missing data (complete case analysis would not be helpful!). Any help is greatly appreciated! Note: I am using SPSS.