All of the stages of bed bugs are visible, at least if you don't need reading glasses and you have a sufficient amount of light. So if you're looking closely enough, you can even see bugs in the nymphal first instar stage. A fecal spot, for its part, can be as large as a bed bug itself in terms of the area it covers. The spots are basically digested blood, so most are dark in color. On a white mattress, they stand out pretty well.
They will starve but not die off completely. That’s why you need to sweep, vacuum, and steam the floors daily. If bed bugs don’t feed on you then they can’t lay eggs. Eventually the numbers will diminish. They might even consider relocating. If you share an apt, it would speed up the process if your housemates do the same thing. It may take months to fully get rid of them but at least you won’t be their meal if you follow me bed proofing instructions.
Unlike those of other insects, bed bug bites may sometimes appear in tight lines of multiple, small, red marks where multiple bed bugs have fed along an exposed area. Bed bug bites can cause itchiness. Initially, a victim may detect a slight burning sensation. The burning area then develops red bumps, known as papules or wheals (rash). In extreme cases, bites may swell dramatically or turn into blister-like skin inflammations.