Working with multiple versions could get complex unless you use different paths for installation.
The command line variable PREFIX can be used to specify the root directory where all the files deployed by make install will be copied.
Assuming you want to install version 3.3. to /usr/local/kamailio-3.3 and you checked out branch 3.3, then run following commands:
make FLAVOUR=kamailio PREFIX=/usr/local/kamailio-3.3 cfg make all make install
All installed files will be located in sub-folders of /usr/local/kamailio-3.3, for example:
To delete this installation, simply remove /usr/local/kamailio-3.3 directory.