Should be gone. Chiggers should bite and release, and not stay adherent to your skin. If there is evidence insect is still attached I would be concerned it is something else such as a tick. To treat the bite use hydrocoritonse and take an antihistamine. If still uncomfortable see your dermatologist for prescription strength treatments.
Immediate soapy bath. The missouri dept. Of conservation says chiggers are baby mites that can only bite through areas of thinner, tender skin (so chiggers like women & children). Chiggers bite to inject saliva to dissolve flesh and eat it up. They do not suck blood nor burrow into the skin. Once scratched, the chigger falls off easily, but the site swells, and itches a lot. A scrubby, soapy bath washes away chiggers.