Is she/he eating at all? If they're eating and not going to the bathroom, that would point to constipation/impaction. Make sure it's drinking water. Drop some on it's nose so it'll lap it up. When you put them in the bath, gently rub they're tummy. Gary ALWAYS goes when I do that. If that still doesn't help, then yes, I would recommend a vet visit.
They can go much longer at times between poos , but as the others mentioned warm bath daily along with a few natural laxatives will do the trick, no need for a vet. Try any of these or a combo of them...applesauce, canned pumpkin [ no spices ] baby food prunes , squash and a few drops of veg.oil and/or honey.
Thanks to all for the advice. I ended up changing the bulb to raise temps and feeding squash baby food. This with a warm bath everynoghtto for about a week. She has pooped twice and it is normal looking. What a relief.