Woke up with bites on my butt. bedbugs?

Could be: Or it could be you were bit the day before and there was just a delay before the red marks showed up. Were you outside sitting in the grass the day before? Check your mattress for signs of bed bugs.

Not sure, depends.: It depends on what the bites look like. Bedbug bites have a blotchy, smudgy, red appearance. They also remain close to their hosts, and in beds and couches, and they tend to have the smell of over-ripe rasberries. Other insects and parasites can cause bites. Scabies have a dark, wavy line burrow with a bleb at the end, and lice and ticks also bite. Itching is also common.

Maybe not: Bed bug bites may have no sx's/signs except for 2 small skin puncture points. A reaction may show from an hr to several days later. It can cause itchy, pink, swollen, lesions w clear center. If hypersensitive blisters may occur. Telltale sign is linear track of lesions from sequential feedings – but doesn't always occur. Bites are in areas exposed while sleeping-arms, shoulders, neck ; legs.