Thanks for asking a question on www.thisisyourbible.com.
Your question indicates the need to always examine the context of a passage as the first step towards understanding its meaning.
If you look at Exodus 4 verses 1-9. The signs are Moses' rod becoming a serpent and then the serpent becoming a rod again; Moses' hand becoming leprous and then becoming healthy; water from the river when poured out onto the dry land will become blood;
I hope you have found this helpful.