Next week's episodes of the soap see Lisa tell her friends and family that she was sexually assaulted by Derek Benrose (Stephen Bent) after suffering in silence for several weeks.
Lisa makes her confession after noticing that Derek is getting close to Lizzie Lakely (Kitty McGeever), making her realise that she has to speak up.
Speaking about the impact of Lisa's decision, Cox told Inside Soap: "It's very difficult for Lizzie to comprehend - but most people know Lisa well enough to take her at her word."
She continued: "I don't think she could have gone much longer in that situation alone. The burden has been like a volcano waiting to erupt so there's definitely a sense of relief. But Lisa has opened a whole new can of worms now."
Following Lisa's confession, it will not be immediately clear whether Derek will be brought to justice.
Cox added: "The police are kind but they're aware of how long it's taken Lisa to come forward, and that may jeopardise any investigation. The question now is whether there's enough evidence."
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