I have a huge filling that fell out and now the nerve is exposed. Can I use Dentek temparin Max to fill the hole? (Photo)

From the picture you sent it looks like a large dental filling, it is best to see your dentist as soon as possible! Over the counter fillings from the pharmacy could be messy, and can interfere with bond to your final restoration.  If temperature sensitivity, try to put wax ( orthodontic, for braces), till you see your dentist asap.

I don't recommend to use any OTC temp. filling from a pharmacy. Due to lack of supervision, we don't know what exactly is in some of them. Sometimes they make the situation worse. I think you should contact your dentist ASAP to replace the filling. 
Good luck!