Whatever you do, do not increase the fuse size to “correct” your problem.
Since the fuse blew previously, and the MIL is on now, it suggests the possibility there is a polarity reversal, or a wiring harness fault, or even that the horn is defective.
When the MIL is on, with the engine running and the transmission in neutral, lower the side stand and the light will flash out the fault code. Knowing the code might help identify what has gone wrong. I believe when the fault no longer exists, the light will go off.
Here is a thread about the MIL: How to read MIL code by myself?
There are probably other threads about the MIL, which you’re free to search for.