Look through your lotion, compare what the substances for the
lotion and sunscreen...
Most lotions provide up to SPF30 and sunscreens can provide up to
SPF130. Of course there are different sunscreens for body
applications and face applications, it's further categories into
Sports, Normal and Kids use...
Some lotions can only screen off UVA or UVB rays, which are the
real rays that harm our skin...
If in doubt, can always ask a beautician or a pharmist...