Carmel is currently struggling to cope following the news that she will be permanently scarred after a tanning machine exploded in her face.
Merna appeared on This Morning today (June 26) and revealed that she is delighted with the emotional plot.
Pictured: Gemma Merna on This Morning today.
The actress commented: "She is a comedy character to start off with, but I'm quite lucky at Hollyoaks because they do give me the serious storylines to get your teeth into.
"We kind of came to that point really - especially with her husband getting shot - that we didn't really know where to take Carmel. We kind of wanted a hard-hitting storyline that people can look at. It changes the character ongoing as well, so I think this one's absolutely fantastic for her."
She continued: "[Carmel] just doesn't know what to do, because she's always wanted a perfect life, a gorgeous husband, lovely children - and the thing that hits her now is [the fear that] no-one will fancy her anymore, no-one will want to be with her. So it took her to the point that we saw last week where she went to the top of the roof to possibly jump off and commit suicide."
Pictured: Carmel in hospital in an upcoming Hollyoaks episode.
Merna confessed that she cried real-life tears when filming scenes which saw characters looking startled by Carmel's appearance.
She said: "It really upset me at work, to be honest. Because I've always been this bubbly character that's always had make-up on every day and looked glamorous, when I had the [injury] make-up on and they did a scene… some of the characters, the way they looked at me, it really made me cry to be honest, which was fantastic for the scene."
Urging the public not to use sunbeds, Merna added: "Skin cancer awareness is very important to me because I'm naturally a very pale person and I got pressured to go on sunbeds when I was 15 and I used to burn.
"We're such a nation of tanning yourself, but there's great fake tans. It's like, just stay off sunbeds because there's so much damage that can be caused by them."
Hollyoaks airs weeknights at 6.30pm on Channel 4, with first look screenings at 7pm on E4.