Hi Hun, I'm just over 28 weeks now and I swapped my metal one for a plastic one about 25 weeks, the metal one had become sore. I looked on the internet for ages, but actually found a plastic one in Argos belv it or not, and quite cheap too!! So I thought I would give it a go...its been fine, no longer sore and have plenty of room up and down. I'm just taking every week as it comes as I dont really want to lose it as it took me ages to have it done.
I dont have one stretch mark from pregnancy yet, so just keep using your bio oil etc twice daily and use the plastic bar and you should be fine...I think the plastic ones are less irratant to your skin too! GOOD LUCK xx