Evening

One of our 4 and a half week old bottle lambs has bloated out tonight, he's feeling quite sorry for himself and hanging about in the corner of the shed looking very uncomfortable.
I have heard his rumen rumble but it seems slow. I've given him some ginger in water drench and we had a small burp but he's still looking sad.
currently they have 2 bottles of 450ml lamlac, creep feed which they nibble at and access to fresh grass.
Is there anything else I should do? should I change their feeding plan (more feeds but smaller quantity?) the other 2 are fine.
thank you in advance