My teeth are shocking; what do I do? (Photo)

! I'm 30 years old and never looked after them (It wasn't taught in childhood and I guess it just never became habit for me. They are now turning black full of holes and one has just fallen out in my hand with no pain or blood, I'm too embarrassed, ashamed and scared to go dentist as I've had a bad experience before but I can't carry on like this anymore I just want to feel normal instead of locking myself away and being scared to smile

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