Get lots of ingrown hairs in groin area. I have one now size of a large pea and the whole thing inside looks very dark to black in colour. Worried?

Please. Please see a dermatologist as soon as possible to have this lesion evaluated for cancer. You may need a biopsy.
Ingrown hairs are. common. You may want to consider laser hair removal to permanently remove the hair, but meanwhile you need to have the buried hair extracted by your doctor. And may need some topical or oral antiinflammatories.