You’re in control of the session and you decide what to say and what to avoid. If you want to lie then that’s entirely up to you and the Hypnotist has no control over that.
Hypnosis isn’t a truth drug and what you say is down to your own mind.
In most countries Hypnosis isn’t allowed as a tool for accessing the truth because it is too open to mistakes. In the 1980’s a (well intentioned) hypnotherapist came across a patient who had (allegedly) been abused as a child whilst staying in a care home. The hypnotherapist searched and hypnotised other children from the care home and a pattern of abuse was discovered covering almost the entire staff. It sounds horrifying until you discover that the Hypnotherapist was asking directed questions (e.g. When did x abuse you?) rather than open, ambiguous questions (e.g. were you aware of any inappropriate behaviour?). This led to many court battles and the end of ‘Repressed Memories’ hypnosis which caused all of the problems in the first place.
So, no you can’t be forced to tell the truth, nor can a hypnotist spot a lie.