Dear Hard Worker !!!
YES your degree is valid.
Subject to complying with the below mentioned pre-conditions.
Whether it is done from Accredited University i.e., recognised one.
Whether your employment terms and conditions permit you to do the same while working.
If the above are complied it is valid.
In all probability if it is done as a regular / full time course while working it is not valid, other way round if it is part time / week end course it is valid.
Good Luck for your Future, May God Bless You with Lots of Success……….