You should not use this switch again until it is looked at by an electrician, unless you are capable of repairing or replacing it yourself.
The fact that it is getting hot indicates that there is a bad connection inside the switch and you are getting electrical arcing, which is a dangerous situation that could potentially cause a fire. The fishy smell is probably caused by overheated plastic, which adds to my concern.
Please get someone to look at this before you use it again.
Answers & Comments
You should not use this switch again until it is looked at by an electrician, unless you are capable of repairing or replacing it yourself.
The fact that it is getting hot indicates that there is a bad connection inside the switch and you are getting electrical arcing, which is a dangerous situation that could potentially cause a fire. The fishy smell is probably caused by overheated plastic, which adds to my concern.
Please get someone to look at this before you use it again.