I have lost the changes I made to the data

When you leave INZight or iNZight Lite, all changes you have made to the data will be lost unless you export your data set before quitting.
When you refresh the webpage in INZight Lite the same thing happens.

The solution is to Export your data using the RData format (as below) before exiting/refreshing.

Exporting data to save changes

To save your data without losing any the changes you have made, go File > Export and export using the RData format.
When you Import this exported data set (which will have a .RData filename extension) the data imported into iNZight will be just as you left it.

For desktop iNZight, see User Guide paragraph on exporting data

Saving a survey-design specification as well as the data

Currently this can only be done using the Save/Load feature for iNZight sessions which is still in developmental mode.

To enable this go File > Preferences and click the checkbox for Enable developmental features. The next time you start iNZight the File menu will give you the ability to Save a session. The saved file will have the filename extension.inzsave. Saved sessions are read into iNZight using Load.