Can you see bed bugs with a magnifying glass?

Yes, if they've been around to drink your blood for long enough to grow big. google images of them.

Correcting above = All bedbugs are visible to the naked eye. The newly born nymphs being about a millimeter which is about a fifth of the size of an adult bedbug. The unhatched eggs are much smaller looking like and being just half the size of a grain of salt before the egg hatches but the bedbug eggs too can be seen with the naked eye unless the viewer is poor sighted. But when bedbugs come out and crawl on to you to sip your blood it will normally be dark and you will most probably be fast asleep. So you will not see them unless you happen to awaken and shine a torch on to yourself and your sheet before they escape to their hiding place.