Bite of sort possible spider bite. started as a blister and not red and inflamed. been over a week?

More history or info: Sorry but not enough info provided. Painful? Single lesion or multiple blisters? Spreading? Itchy? Location? Changing since onset?

Possible????: Unless you saw and felt the attack, then took the creature to an expert for precise identification, assume it is NOT a "spider bite" but something else. Now you can consult a health pro, preferably a dermatologist, for a definition of the situation and best remedy. Look up black button and brown button spiders so you can recognize them. There are numerous skin conditions presenting as blisters.