I note that you have generously been applying tenovate for your lichen planus, even during your pregnancy. Please discontinue it altogether or apply a small amount only if you have to. Milder steroid creams such as Locoid may be better though the best thing for you would be to avoid all kinds of steroids particularly the strong ones which get absorbed through the skin.
Having cautioned you about the steroids, I wish one could say that what effect the application you have made is going to have on the unborn child. There is some evidence about ill-effects of steroids but these are more with internal consumption; than with local applications. I think the best thing for you would be to stay in touch with your obstetrician who could monitor the childs progress from time to time. There may not be cause for undue concern, though.
I wish your child and you all the best.