Your child may not need counselling or therapy - they may cope with it without being traumatised, but clearly this does depend on your reaction as well I am afraid.
This may be true for some children, but not all!
DD was sexually assaulted, aged 8 by a 7 year old boy in her class. She came home and didn’t say a word to me. However, she was having child psychotherapy at Camhs; and happened to have it that day. She disclosed the assault to the psychotherapist, who told me afterwards. There was a Wendy house in the classroom. The ten children (a specialist resource unit for SEN children in a class of ten) were all in the Wendy House at break time. The teacher and two TAs were busy chatting to each other. The boy pulled her trousers down, and lay on top of her, kissing her. All the children were watching. DD thought he had had sex with her, and she was pregnant. That’s why she didn’t tell me, as she thought I’d be angry she was pregnant.
The psychotherapist commented DD had all the emotions and reactions of a victim of CSA; and it could have a long term effect on her relationships with men. (Actually, it has had a long term effect on her relationships with other people, not just men. Her recall 20 years later is still immediate.)
DD also told me, when she walked past the toilets, on the way to the classroom, he sat on the toilet, with the door open, waving his penis at her. She had told three members of staff, who told her “not to tell tales”! Actually, the nature of her SEN was that she did not really understand lying - she tells the truth, as she sees it.
The psychotherapist informed the school, and either she or the school reported it to Children’s Social Services. Social Services investigated the family. They also rang me up to offer support.
The mother told me, he had been watching East Enders and copied behaviour off there. (The head arranged for her to meet us and apologise to us. I was horrified and didn’t want to meet her; but he sprang it on us, before her annual review of her SEN, already arranged)
The class teacher came to our house unannounced to apologise - the boy had behavioural problems and didn’t belong in DD’s class; he should have been in a mainstream class. The head put him in DD’s specialist unit, to get him out of the hair of the mainstream teachers; against her advice. The school sacked her! IMO, she was scapegoated!
Years later, Social Services told me a Management meeting should have been held with us, to discuss a strategy for the future.