Using a continuous glucose monitor

Q: I am, as per blood results and my doctor, on the brink of Type 2 diabetes. One of the options to try and reverse this is to use a continuous glucose monitor. What is the position with this in terms of ghusl? 

The patch is kept on for 14 days at a time and then changed. Please advise what is the position in terms of ghusl as if we are required to remove this in ghusl then it cannot work as each patch costs almost R1500 per 2 weeks.

The minimum time period of a salam transaction in the Hanafi mazhab

Q: I had learnt in madrasah that among the conditions for the permissibility of a salam transaction is that the period of time from the date of the sale until the date of delivery should be a minimum of one month. If the salam period is less than one month, then the transaction will not be permissible and will not be valid. 

However, I was recently informed that there is another opinion in the Hanafi Mazhab, that even if the the period of time from the date of the sale until the date of delivery is less than one month, the salam transaction will be permissible provided that there is an urf of that nature in the place where one is staying. Is this the correct view in the Hanafi Mazhab?