This may or may not be a scam, but the moral of the story is: nothing good ever happened from on-line sex. See Texas Penal Code Section 33.021 - Online Solicitation of a Minor for the law on the subject. Whether you are subject to potential prosecution depends on the exact nature of the correspondence. Go meet with a local attorney and bring the contents to hopefully put your mind at ease.
This sounds like a common scam to me. The father also wanted you to pay something, right? You should report this to the police. There was no girl. It was all a scam to get money out of you.
1) Delete the photos.
2) Block the number.
3) Do not respond to them.
It is probably a scam. This happens with greater and greater frequency, but, if it is not, then sop long as you destroy and neither store nor disseminate the images you should be just fine.
Wishing you luck and hoping that I have been helpful in answering your question.