Unit transfer

So I recently was rehired at a local hospital. I used to work there for over a year as a medical surgical RN. I left to try out m-F nursing. I didn’t end up liking 5 days a week. So long story short, I am back at my old medical surgical unit. In the short 3 weeks I’ve been there, I already feel like I putting my license at risk. I had 6 patients the other day (which isn’t unusual) but one was hourly CWAI, another hourly accuchecks. I never even received report on one of my patients, the night shift nurse just left. There is an opening in another unit at the hospital that I am wanting to transfer too. I was offered the job by the hiring manager, but my now manager won’t let me transfer due to complaint policy at new hires must have 6 months of experience in the current position before internal transfer. My concern is if I stay at my job, I am at risk of putting my patients in harms way, or even losing my license.  Advice?