Well, we need to know if you want to attempt to fix this problem yourself or if you are going to a mechanic or friend for further help ?
If the fuses which blew are in the fuse box inside the car, that fuse box and it's related electronics are called the Smart Junction Box, as mentioned by others in above posts.
If water gets into that box, which it can, depending on just where your water leak was from, then water can create numerous problems. If you had no electrical problems before the water leak , but do now, either water is still leaking into the SJB, or corrosion has started from a previous leak. If water is currently inside that fuse box, drying the water out might fix the problem of blowing fuses, but someone then must figure out if there is still a leak which was not properly fixed in the past attempt.
We need more information from you as to which fuses blew...which numbered fuses in the Mustang Owner's Guide (glove box manual).
Is there any chance that your car is still under Ford Factory Warranty, or are you on your own at this point ?
We do also have available a Technical Service Bulletin which describes how to diagnose a water leak into the front floor area of these cars. Attaching same, which has wording, tech illustrations, and a very clear picture of areas where water can leak into cabin of car. Maybe your water leak was not completely fixed and needs further diagnosis ?
Please let us know if you need further help or advise about how to deal with the problem or who is going to work on it.