How to use an insert using variable column names in stored procedure

I am sure that this happens because of my lack of knowledge, but I am in a dead end here. I am trying to pass a parameter from a stored procedure in order to use insert or update based on that parameter as a column name.

For example, I am trying to use this commands inside a stored procedure:

set @value = 'comment'; execute immediate concat('update log set ',@value,'= ?') USING 'lalalala';

However, when I use this concat inside a stored procedure, it just doesn't allow me, or in case of an insert doesn't do anything or makes the database freeze. What am I doing wrong? how can I make a stored procedure pass a column name as a parameter in order to use it on a successful insert/update?

I also tried to use the PREPARE / EXECUTE pair as well, but for no avail Please, any help would be welcome!